<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e64c7-4989-7a47-9a45-f8a68311fb6c,g:8cc07d50-e050-45ac-b6d1-f93e6cba5424-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.midlandsb.com/role/CoverPage" xlink:type="simple" xlink:href="msbi-20260630.xsd#CoverPage"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/CoverPage" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_019e64c7-548c-77bf-b439-0830c4108f32" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_DocumentInformationTable_019e64c7-548c-77bf-b439-0830c4108f32" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e64c7-548c-7ab2-9f03-a3398f963b76" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_019e64c7-548c-77bf-b439-0830c4108f32" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e64c7-548c-7ab2-9f03-a3398f963b76" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64c7-548c-7ab2-9f03-a3398f963b76_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64c7-548c-7ab2-9f03-a3398f963b76" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64c7-548c-7ab2-9f03-a3398f963b76_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e64c7-548c-7272-ba2d-20e09c73d187" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e64c7-548c-7ab2-9f03-a3398f963b76" xlink:to="loc_us-gaap_ClassOfStockDomain_019e64c7-548c-7272-ba2d-20e09c73d187" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e64c7-548c-7a1f-885d-7d9d7ff82932" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64c7-548c-7272-ba2d-20e09c73d187" xlink:to="loc_us-gaap_CommonStockMember_019e64c7-548c-7a1f-885d-7d9d7ff82932" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_DepositorySharesMember_019e64c7-548c-74e3-837b-0376e9fdcc42" xlink:href="msbi-20260630.xsd#msbi_DepositorySharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e64c7-548c-7272-ba2d-20e09c73d187" xlink:to="loc_msbi_DepositorySharesMember_019e64c7-548c-74e3-837b-0376e9fdcc42" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019e64c7-548c-7014-87a1-ca1cc9d1c48e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_DocumentType_019e64c7-548c-7014-87a1-ca1cc9d1c48e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentQuarterlyReport_019e64c7-548c-79fe-a62a-ac2f49c641f0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentQuarterlyReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_DocumentQuarterlyReport_019e64c7-548c-79fe-a62a-ac2f49c641f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019e64c7-548c-7c38-86ba-fef4b9c346e9" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_DocumentPeriodEndDate_019e64c7-548c-7c38-86ba-fef4b9c346e9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_019e64c7-548c-79ea-af20-a3dbda30dcc2" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentTransitionReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_DocumentTransitionReport_019e64c7-548c-79ea-af20-a3dbda30dcc2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019e64c7-548c-783f-aceb-f7f3bd31c440" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityFileNumber_019e64c7-548c-783f-aceb-f7f3bd31c440" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019e64c7-548c-78e5-85f5-bac1af9bd297" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityRegistrantName_019e64c7-548c-78e5-85f5-bac1af9bd297" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019e64c7-548c-7bbf-9b6d-12c23da7876e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019e64c7-548c-7bbf-9b6d-12c23da7876e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019e64c7-548c-76ba-a145-2f07fcd1306b" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityTaxIdentificationNumber_019e64c7-548c-76ba-a145-2f07fcd1306b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019e64c7-548c-7960-a41a-d1bad02d52cc" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityAddressAddressLine1_019e64c7-548c-7960-a41a-d1bad02d52cc" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019e64c7-548c-7f13-8cd9-b4a9a18da814" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityAddressCityOrTown_019e64c7-548c-7f13-8cd9-b4a9a18da814" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019e64c7-548c-79ac-a06f-ae58e8c6c9db" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityAddressStateOrProvince_019e64c7-548c-79ac-a06f-ae58e8c6c9db" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019e64c7-548c-7b51-86bd-544f32c9d842" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityAddressPostalZipCode_019e64c7-548c-7b51-86bd-544f32c9d842" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019e64c7-548c-7444-a553-9e793817db4a" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_CityAreaCode_019e64c7-548c-7444-a553-9e793817db4a" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019e64c7-548c-7347-8fd3-336b905a2615" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_LocalPhoneNumber_019e64c7-548c-7347-8fd3-336b905a2615" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019e64c7-548c-7f8e-af61-42aa66c50236" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_Security12bTitle_019e64c7-548c-7f8e-af61-42aa66c50236" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019e64c7-548c-79b4-b167-5797228f518a" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_TradingSymbol_019e64c7-548c-79b4-b167-5797228f518a" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019e64c7-548c-7d08-86c3-7564eadf73d1" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_SecurityExchangeName_019e64c7-548c-7d08-86c3-7564eadf73d1" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_019e64c7-548c-7d8a-a964-0bca908f7873" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCurrentReportingStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityCurrentReportingStatus_019e64c7-548c-7d8a-a964-0bca908f7873" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_019e64c7-548c-730b-ade5-6b6410753697" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityInteractiveDataCurrent_019e64c7-548c-730b-ade5-6b6410753697" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_019e64c7-548c-77a8-a44b-35a02d016011" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFilerCategory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityFilerCategory_019e64c7-548c-77a8-a44b-35a02d016011" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_019e64c7-548c-7ecf-8190-5317c93a8422" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntitySmallBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntitySmallBusiness_019e64c7-548c-7ecf-8190-5317c93a8422" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019e64c7-548c-7f53-846b-3060eca243c1" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityEmergingGrowthCompany_019e64c7-548c-7f53-846b-3060eca243c1" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_019e64c7-548c-7769-bdb5-932b19f61895" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityShellCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityShellCompany_019e64c7-548c-7769-bdb5-932b19f61895" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_019e64c7-548c-7bc7-9db7-a46b1ac47a69" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_019e64c7-548c-7bc7-9db7-a46b1ac47a69" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019e64c7-548c-7964-b09e-7368dd97fbcb" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_EntityCentralIndexKey_019e64c7-548c-7964-b09e-7368dd97fbcb" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019e64c7-548c-75e9-8d74-f538a416aca4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_AmendmentFlag_019e64c7-548c-75e9-8d74-f538a416aca4" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_019e64c7-548c-7c90-a4e6-a3073ca89f0d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_CurrentFiscalYearEndDate_019e64c7-548c-7c90-a4e6-a3073ca89f0d" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_019e64c7-548c-79cb-add0-f585042004b6" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentFiscalYearFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_DocumentFiscalYearFocus_019e64c7-548c-79cb-add0-f585042004b6" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_019e64c7-548c-7863-b640-e9788491a5f2" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e64c7-548c-797b-9931-f975f9fbb1b1" xlink:to="loc_dei_DocumentFiscalPeriodFocus_019e64c7-548c-7863-b640-e9788491a5f2" xlink:type="arc" order="28"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/CONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITYUNAUDITED" xlink:type="simple" xlink:href="msbi-20260630.xsd#CONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITYUNAUDITED"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/CONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITYUNAUDITED" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e64c7-548d-78f3-a217-566a63b7521e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e64c7-548d-71c8-bc35-62580b38adcf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e64c7-548d-78f3-a217-566a63b7521e" xlink:to="loc_us-gaap_StatementTable_019e64c7-548d-71c8-bc35-62580b38adcf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e64c7-548d-7579-bffe-13bbafe7bdb1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e64c7-548d-71c8-bc35-62580b38adcf" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e64c7-548d-7579-bffe-13bbafe7bdb1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64c7-548d-7579-bffe-13bbafe7bdb1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64c7-548d-7579-bffe-13bbafe7bdb1" xlink:to="loc_us-gaap_EquityComponentDomain_019e64c7-548d-7579-bffe-13bbafe7bdb1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64c7-548d-703d-9087-2176a506ac6a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64c7-548d-7579-bffe-13bbafe7bdb1" xlink:to="loc_us-gaap_EquityComponentDomain_019e64c7-548d-703d-9087-2176a506ac6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e64c7-548d-7e70-a6b9-b0a7f686c905" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64c7-548d-703d-9087-2176a506ac6a" xlink:to="loc_us-gaap_CommonStockMember_019e64c7-548d-7e70-a6b9-b0a7f686c905" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_019e64c7-548d-77f1-a2bb-cbe70242d3fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64c7-548d-703d-9087-2176a506ac6a" xlink:to="loc_us-gaap_PreferredStockMember_019e64c7-548d-77f1-a2bb-cbe70242d3fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_019e64c7-548d-7fda-836a-8497badf514b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64c7-548d-703d-9087-2176a506ac6a" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_019e64c7-548d-7fda-836a-8497badf514b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019e64c7-548d-749d-9d76-f03ede2971fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64c7-548d-703d-9087-2176a506ac6a" xlink:to="loc_us-gaap_RetainedEarningsMember_019e64c7-548d-749d-9d76-f03ede2971fe" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e64c7-548d-7e1e-8af1-e1e1212d013c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64c7-548d-703d-9087-2176a506ac6a" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e64c7-548d-7e1e-8af1-e1e1212d013c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64c7-548d-7ac1-b7f1-4bacfd9d0c87" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e64c7-548d-78f3-a217-566a63b7521e" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64c7-548d-7ac1-b7f1-4bacfd9d0c87" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019e64c7-548d-70ec-8397-26f73d55197d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64c7-548d-7ac1-b7f1-4bacfd9d0c87" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019e64c7-548d-70ec-8397-26f73d55197d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e64c7-548d-724c-bf41-9cebea2f4ac1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64c7-548d-7ac1-b7f1-4bacfd9d0c87" xlink:to="loc_us-gaap_StockholdersEquity_019e64c7-548d-724c-bf41-9cebea2f4ac1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e64c7-548d-70e7-9d4b-2f17dae8bea7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64c7-548d-7ac1-b7f1-4bacfd9d0c87" xlink:to="loc_us-gaap_NetIncomeLoss_019e64c7-548d-70e7-9d4b-2f17dae8bea7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e64c7-548d-75da-a9db-6a8e6ca76645" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64c7-548d-7ac1-b7f1-4bacfd9d0c87" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e64c7-548d-75da-a9db-6a8e6ca76645" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_DividendsCommonStockAndShareBasedCompensation_019e64c7-548d-7ab1-a58a-e95aad96933c" xlink:href="msbi-20260630.xsd#msbi_DividendsCommonStockAndShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64c7-548d-7ac1-b7f1-4bacfd9d0c87" xlink:to="loc_msbi_DividendsCommonStockAndShareBasedCompensation_019e64c7-548d-7ab1-a58a-e95aad96933c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPreferredStock_019e64c7-548d-78bd-b1dc-4e7d5ba1b703" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsPreferredStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64c7-548d-7ac1-b7f1-4bacfd9d0c87" xlink:to="loc_us-gaap_DividendsPreferredStock_019e64c7-548d-78bd-b1dc-4e7d5ba1b703" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_019e64c7-548d-75d1-8f8a-9215b0ea00f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64c7-548d-7ac1-b7f1-4bacfd9d0c87" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_019e64c7-548d-75d1-8f8a-9215b0ea00f5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue_019e64c7-548d-728c-a062-5c50eac1c862" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64c7-548d-7ac1-b7f1-4bacfd9d0c87" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodValue_019e64c7-548d-728c-a062-5c50eac1c862" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019e64c7-548d-7799-a8b2-300d8da6dd11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64c7-548d-7ac1-b7f1-4bacfd9d0c87" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019e64c7-548d-7799-a8b2-300d8da6dd11" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeBenefitPlan_019e64c7-548d-724b-8b5b-e4e575220e50" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeBenefitPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64c7-548d-7ac1-b7f1-4bacfd9d0c87" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeBenefitPlan_019e64c7-548d-724b-8b5b-e4e575220e50" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeBenefitPlan_019e64c7-548d-75e2-a117-cf7f95738188" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeBenefitPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e64c7-548d-7ac1-b7f1-4bacfd9d0c87" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeBenefitPlan_019e64c7-548d-75e2-a117-cf7f95738188" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019e64c7-548d-7bc4-9cfb-42d7b9c935d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e64c7-548d-769e-9f5e-ff04ef62f1b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/INVESTMENTSECURITIESClassifiedDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#INVESTMENTSECURITIESClassifiedDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/INVESTMENTSECURITIESClassifiedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e64c7-5561-71b0-aa1d-49e3186c41fc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarketableSecuritiesTable_019e64c7-5561-774c-865c-ca355de68588" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MarketableSecuritiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e64c7-5561-71b0-aa1d-49e3186c41fc" xlink:to="loc_us-gaap_MarketableSecuritiesTable_019e64c7-5561-774c-865c-ca355de68588" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5561-7e16-9f59-f75d9b0fd1ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_MarketableSecuritiesTable_019e64c7-5561-774c-865c-ca355de68588" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5561-7e16-9f59-f75d9b0fd1ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-7e16-9f59-f75d9b0fd1ed_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5561-7e16-9f59-f75d9b0fd1ed" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-7e16-9f59-f75d9b0fd1ed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-70bf-9517-2ffd249b7e96" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5561-7e16-9f59-f75d9b0fd1ed" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-70bf-9517-2ffd249b7e96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_019e64c7-5561-7a48-988a-3db48066b099" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-70bf-9517-2ffd249b7e96" xlink:to="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_019e64c7-5561-7a48-988a-3db48066b099" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_AgencyMortgageBackedSecuritiesMember_019e64c7-5561-7930-840c-ccc8d3d68a7b" xlink:href="msbi-20260630.xsd#msbi_AgencyMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-70bf-9517-2ffd249b7e96" xlink:to="loc_msbi_AgencyMortgageBackedSecuritiesMember_019e64c7-5561-7930-840c-ccc8d3d68a7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_NonagencyMortgageBackedSecuritiesMember_019e64c7-5561-7aae-8c24-4255c0647ad9" xlink:href="msbi-20260630.xsd#msbi_NonagencyMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-70bf-9517-2ffd249b7e96" xlink:to="loc_msbi_NonagencyMortgageBackedSecuritiesMember_019e64c7-5561-7aae-8c24-4255c0647ad9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_StudentLoanAssetBackedMember_019e64c7-5561-7a8c-9354-a229da4e6f4b" xlink:href="msbi-20260630.xsd#msbi_StudentLoanAssetBackedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-70bf-9517-2ffd249b7e96" xlink:to="loc_msbi_StudentLoanAssetBackedMember_019e64c7-5561-7a8c-9354-a229da4e6f4b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e64c7-5561-75f6-945a-c29cfc5d3459" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-70bf-9517-2ffd249b7e96" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e64c7-5561-75f6-945a-c29cfc5d3459" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralizedLoanObligationsMember_019e64c7-5561-7dc5-a9c8-0d424b2b7d3d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralizedLoanObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-70bf-9517-2ffd249b7e96" xlink:to="loc_us-gaap_CollateralizedLoanObligationsMember_019e64c7-5561-7dc5-a9c8-0d424b2b7d3d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CorporateDebtAndEquitySecuritiesMember_019e64c7-5561-76e6-bced-3a5749613b61" xlink:href="msbi-20260630.xsd#msbi_CorporateDebtAndEquitySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-70bf-9517-2ffd249b7e96" xlink:to="loc_msbi_CorporateDebtAndEquitySecuritiesMember_019e64c7-5561-76e6-bced-3a5749613b61" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_019e64c7-5561-77fa-a5d6-7d630b2a7287" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e64c7-5561-71b0-aa1d-49e3186c41fc" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_019e64c7-5561-77fa-a5d6-7d630b2a7287" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e64c7-5561-7d13-b740-340e8e5ce023" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_019e64c7-5561-77fa-a5d6-7d630b2a7287" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e64c7-5561-7d13-b740-340e8e5ce023" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_019e64c7-5561-7889-b988-78c30713a6ce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_019e64c7-5561-77fa-a5d6-7d630b2a7287" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_019e64c7-5561-7889-b988-78c30713a6ce" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_019e64c7-5561-7ae9-b6da-c646743096b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_019e64c7-5561-77fa-a5d6-7d630b2a7287" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_019e64c7-5561-7ae9-b6da-c646743096b5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e64c7-5561-71dc-9403-7ecaf662c38a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_019e64c7-5561-77fa-a5d6-7d630b2a7287" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e64c7-5561-71dc-9403-7ecaf662c38a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgedAssetFairValueHedgeLastOfLayerCumulativeIncreaseDecrease_019e64c7-5561-78ed-af4b-2c6bdc8f37af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgedAssetFairValueHedgeLastOfLayerCumulativeIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_019e64c7-5561-77fa-a5d6-7d630b2a7287" xlink:to="loc_us-gaap_HedgedAssetFairValueHedgeLastOfLayerCumulativeIncreaseDecrease_019e64c7-5561-78ed-af4b-2c6bdc8f37af" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/INVESTMENTSECURITIESAllowanceforCreditLossandUnrealizedLossesandFairValuesDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#INVESTMENTSECURITIESAllowanceforCreditLossandUnrealizedLossesandFairValuesDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/INVESTMENTSECURITIESAllowanceforCreditLossandUnrealizedLossesandFairValuesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e64c7-5561-79cd-b861-9c2e0db5559c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e64c7-5561-78d4-b4fd-3da4dda2dcf1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e64c7-5561-79cd-b861-9c2e0db5559c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e64c7-5561-78d4-b4fd-3da4dda2dcf1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5561-7d45-a2a5-c4679b436601" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e64c7-5561-78d4-b4fd-3da4dda2dcf1" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5561-7d45-a2a5-c4679b436601" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-7d45-a2a5-c4679b436601_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5561-7d45-a2a5-c4679b436601" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-7d45-a2a5-c4679b436601_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-7271-adc8-6b88c83b42e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5561-7d45-a2a5-c4679b436601" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-7271-adc8-6b88c83b42e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_019e64c7-5561-7045-9a53-1ca1fe2feaa3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-7271-adc8-6b88c83b42e3" xlink:to="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_019e64c7-5561-7045-9a53-1ca1fe2feaa3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_AgencyMortgageBackedSecuritiesMember_019e64c7-5561-7495-b988-8ce1c3aea143" xlink:href="msbi-20260630.xsd#msbi_AgencyMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-7271-adc8-6b88c83b42e3" xlink:to="loc_msbi_AgencyMortgageBackedSecuritiesMember_019e64c7-5561-7495-b988-8ce1c3aea143" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_NonagencyMortgageBackedSecuritiesMember_019e64c7-5561-71ef-abac-2f855c9a1eba" xlink:href="msbi-20260630.xsd#msbi_NonagencyMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-7271-adc8-6b88c83b42e3" xlink:to="loc_msbi_NonagencyMortgageBackedSecuritiesMember_019e64c7-5561-71ef-abac-2f855c9a1eba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_StudentLoanAssetBackedMember_019e64c7-5561-72a6-909a-f39b8650636a" xlink:href="msbi-20260630.xsd#msbi_StudentLoanAssetBackedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-7271-adc8-6b88c83b42e3" xlink:to="loc_msbi_StudentLoanAssetBackedMember_019e64c7-5561-72a6-909a-f39b8650636a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e64c7-5561-7aa6-a263-9d0fdae64986" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-7271-adc8-6b88c83b42e3" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e64c7-5561-7aa6-a263-9d0fdae64986" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralizedLoanObligationsMember_019e64c7-5561-70b2-9f3f-b83cce2a941d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralizedLoanObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-7271-adc8-6b88c83b42e3" xlink:to="loc_us-gaap_CollateralizedLoanObligationsMember_019e64c7-5561-70b2-9f3f-b83cce2a941d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CorporateDebtAndEquitySecuritiesMember_019e64c7-5561-721b-ac51-d18a3163ff22" xlink:href="msbi-20260630.xsd#msbi_CorporateDebtAndEquitySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5561-7271-adc8-6b88c83b42e3" xlink:to="loc_msbi_CorporateDebtAndEquitySecuritiesMember_019e64c7-5561-721b-ac51-d18a3163ff22" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValuesAbstract_019e64c7-5561-7148-bd37-16cc2f5af2d6" xlink:href="msbi-20260630.xsd#msbi_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e64c7-5561-79cd-b861-9c2e0db5559c" xlink:to="loc_msbi_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValuesAbstract_019e64c7-5561-7148-bd37-16cc2f5af2d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_019e64c7-5561-7797-a545-2c98781c50d3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_msbi_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValuesAbstract_019e64c7-5561-7148-bd37-16cc2f5af2d6" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_019e64c7-5561-7797-a545-2c98781c50d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_019e64c7-5561-74f3-a320-8a636f041186" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_msbi_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValuesAbstract_019e64c7-5561-7148-bd37-16cc2f5af2d6" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_019e64c7-5561-74f3-a320-8a636f041186" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_019e64c7-5561-7ad0-8fb0-e312ed49bf1a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_msbi_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValuesAbstract_019e64c7-5561-7148-bd37-16cc2f5af2d6" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_019e64c7-5561-7ad0-8fb0-e312ed49bf1a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_019e64c7-5561-7b04-a1cd-ec9c4d6622ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_msbi_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValuesAbstract_019e64c7-5561-7148-bd37-16cc2f5af2d6" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_019e64c7-5561-7b04-a1cd-ec9c4d6622ed" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_019e64c7-5561-71ff-b29e-296544dd2884" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_msbi_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValuesAbstract_019e64c7-5561-7148-bd37-16cc2f5af2d6" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_019e64c7-5561-71ff-b29e-296544dd2884" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_019e64c7-5561-7250-93b3-cd7dd2efa918" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_msbi_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValuesAbstract_019e64c7-5561-7148-bd37-16cc2f5af2d6" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_019e64c7-5561-7250-93b3-cd7dd2efa918" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/LOANSSummaryofLoansandCreditLossesDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#LOANSSummaryofLoansandCreditLossesDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/LOANSSummaryofLoansandCreditLossesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-7578-a96b-020e7a1b9330" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7f00-8e1c-dd567eb94dca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-7578-a96b-020e7a1b9330" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7f00-8e1c-dd567eb94dca" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7c6f-9b82-7572ef592239" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7f00-8e1c-dd567eb94dca" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7c6f-9b82-7572ef592239" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7c6f-9b82-7572ef592239_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7c6f-9b82-7572ef592239" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7c6f-9b82-7572ef592239_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7003-8f29-b09cec84ae52" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7c6f-9b82-7572ef592239" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7003-8f29-b09cec84ae52" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialLoanMember_019e64c7-5561-78b6-87e7-00f5ae35523b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7003-8f29-b09cec84ae52" xlink:to="loc_us-gaap_CommercialLoanMember_019e64c7-5561-78b6-87e7-00f5ae35523b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-7f3e-b3fa-f3eda3dd2236" xlink:href="msbi-20260630.xsd#msbi_CommercialOtherLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7003-8f29-b09cec84ae52" xlink:to="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-7f3e-b3fa-f3eda3dd2236" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019e64c7-5561-7403-b445-6bc231c1db7f" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateNonOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7003-8f29-b09cec84ae52" xlink:to="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019e64c7-5561-7403-b445-6bc231c1db7f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019e64c7-5561-7441-9b87-796b3a441a5d" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7003-8f29-b09cec84ae52" xlink:to="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019e64c7-5561-7441-9b87-796b3a441a5d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_019e64c7-5561-79f6-a022-74fbe6bdd956" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7003-8f29-b09cec84ae52" xlink:to="loc_srt_MultifamilyMember_019e64c7-5561-79f6-a022-74fbe6bdd956" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FarmlandLoansMember_019e64c7-5561-7eb6-a2e4-a87ce429b9f6" xlink:href="msbi-20260630.xsd#msbi_FarmlandLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7003-8f29-b09cec84ae52" xlink:to="loc_msbi_FarmlandLoansMember_019e64c7-5561-7eb6-a2e4-a87ce429b9f6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-7c41-8675-8d5cfcdd3dfa" xlink:href="msbi-20260630.xsd#msbi_ConstructionAndLandDevelopmentLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7003-8f29-b09cec84ae52" xlink:to="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-7c41-8675-8d5cfcdd3dfa" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-70bf-a2bd-e93dba48359d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7003-8f29-b09cec84ae52" xlink:to="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-70bf-a2bd-e93dba48359d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-7835-9a49-32a0f1573872" xlink:href="msbi-20260630.xsd#msbi_OtherResidentialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7003-8f29-b09cec84ae52" xlink:to="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-7835-9a49-32a0f1573872" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerLoanMember_019e64c7-5561-7856-aa92-58cbdff2f4ec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7003-8f29-b09cec84ae52" xlink:to="loc_us-gaap_ConsumerLoanMember_019e64c7-5561-7856-aa92-58cbdff2f4ec" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherConsumerLoansMember_019e64c7-5561-7a71-b9bc-0e2d689eb848" xlink:href="msbi-20260630.xsd#msbi_OtherConsumerLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7003-8f29-b09cec84ae52" xlink:to="loc_msbi_OtherConsumerLoansMember_019e64c7-5561-7a71-b9bc-0e2d689eb848" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-717e-90ba-d469309390fc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7f00-8e1c-dd567eb94dca" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-717e-90ba-d469309390fc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-717e-90ba-d469309390fc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-717e-90ba-d469309390fc" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-717e-90ba-d469309390fc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-781a-8ba8-34c4633814d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-717e-90ba-d469309390fc" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-781a-8ba8-34c4633814d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-7ab4-81c3-a6bf9a34adad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-781a-8ba8-34c4633814d4" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-7ab4-81c3-a6bf9a34adad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-7a08-9df3-e728aeabe2dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-781a-8ba8-34c4633814d4" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-7a08-9df3-e728aeabe2dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_019e64c7-5561-73f6-9f72-38369bab3928" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-781a-8ba8-34c4633814d4" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_019e64c7-5561-73f6-9f72-38369bab3928" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasesPortfolioSegmentMember_019e64c7-5561-763b-aaa5-8c4675a11ecb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeasesPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-781a-8ba8-34c4633814d4" xlink:to="loc_us-gaap_FinanceLeasesPortfolioSegmentMember_019e64c7-5561-763b-aaa5-8c4675a11ecb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e64c7-5561-77ed-a96e-9fa9f181ed1e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-7578-a96b-020e7a1b9330" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e64c7-5561-77ed-a96e-9fa9f181ed1e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableDeferredIncome_019e64c7-5561-7bde-88f4-9449aa318c46" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableDeferredIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-7578-a96b-020e7a1b9330" xlink:to="loc_us-gaap_FinancingReceivableDeferredIncome_019e64c7-5561-7bde-88f4-9449aa318c46" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredDiscountsFinanceChargesAndInterestIncludedInReceivables_019e64c7-5561-7c5c-ad20-ef66c84cf7f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredDiscountsFinanceChargesAndInterestIncludedInReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-7578-a96b-020e7a1b9330" xlink:to="loc_us-gaap_DeferredDiscountsFinanceChargesAndInterestIncludedInReceivables_019e64c7-5561-7c5c-ad20-ef66c84cf7f1" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/LOANSLoanstoDirectorsExecutiveOfficersPrincipalShareholdersandAffiliatesDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#LOANSLoanstoDirectorsExecutiveOfficersPrincipalShareholdersandAffiliatesDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/LOANSLoanstoDirectorsExecutiveOfficersPrincipalShareholdersandAffiliatesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_019e64c7-5561-7725-b90b-79a9dbcc44be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e64c7-5561-7cd9-875a-ad43b1068422" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64c7-5561-7725-b90b-79a9dbcc44be" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e64c7-5561-7cd9-875a-ad43b1068422" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64c7-5561-7443-8981-48a1619deac2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e64c7-5561-7cd9-875a-ad43b1068422" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64c7-5561-7443-8981-48a1619deac2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e64c7-5561-7443-8981-48a1619deac2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64c7-5561-7443-8981-48a1619deac2" xlink:to="loc_us-gaap_RelatedPartyDomain_019e64c7-5561-7443-8981-48a1619deac2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e64c7-5561-70e1-80cf-685ba8d3a9b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e64c7-5561-7443-8981-48a1619deac2" xlink:to="loc_us-gaap_RelatedPartyDomain_019e64c7-5561-70e1-80cf-685ba8d3a9b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_DirectorsExecutiveOfficersPrincipalShareholdersAndAffiliatesMember_019e64c7-5561-78a6-929c-a528c9cfee4b" xlink:href="msbi-20260630.xsd#msbi_DirectorsExecutiveOfficersPrincipalShareholdersAndAffiliatesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e64c7-5561-70e1-80cf-685ba8d3a9b4" xlink:to="loc_msbi_DirectorsExecutiveOfficersPrincipalShareholdersAndAffiliatesMember_019e64c7-5561-78a6-929c-a528c9cfee4b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_NotesReceivableRollForward_019e64c7-5561-765a-a2e0-f1df29ef4515" xlink:href="msbi-20260630.xsd#msbi_NotesReceivableRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e64c7-5561-7725-b90b-79a9dbcc44be" xlink:to="loc_msbi_NotesReceivableRollForward_019e64c7-5561-765a-a2e0-f1df29ef4515" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableNet_019e64c7-5561-770f-af3d-e699b7a1e06e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_msbi_NotesReceivableRollForward_019e64c7-5561-765a-a2e0-f1df29ef4515" xlink:to="loc_us-gaap_NotesReceivableNet_019e64c7-5561-770f-af3d-e699b7a1e06e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FinancingReceivableAfterAllowanceForCreditLossAdditions_019e64c7-5561-7756-ab16-54d7f8687520" xlink:href="msbi-20260630.xsd#msbi_FinancingReceivableAfterAllowanceForCreditLossAdditions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_msbi_NotesReceivableRollForward_019e64c7-5561-765a-a2e0-f1df29ef4515" xlink:to="loc_msbi_FinancingReceivableAfterAllowanceForCreditLossAdditions_019e64c7-5561-7756-ab16-54d7f8687520" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FinancingReceivableAfterAllowanceForCreditLossReductions_019e64c7-5561-7295-8447-72ef215b5b9f" xlink:href="msbi-20260630.xsd#msbi_FinancingReceivableAfterAllowanceForCreditLossReductions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_msbi_NotesReceivableRollForward_019e64c7-5561-765a-a2e0-f1df29ef4515" xlink:to="loc_msbi_FinancingReceivableAfterAllowanceForCreditLossReductions_019e64c7-5561-7295-8447-72ef215b5b9f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableNet_019e64c7-5561-7721-97a9-d2777243dc7f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesReceivableNet"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/LOANSSummaryofChangesintheACLonLoansDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#LOANSSummaryofChangesintheACLonLoansDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/LOANSSummaryofChangesintheACLonLoansDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableImpairedLineItems_019e64c7-5561-7601-a479-d10ba75584b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableImpairedLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_019e64c7-5561-72f0-adc7-8db7b38137ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfImpairedFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_019e64c7-5561-7601-a479-d10ba75584b7" xlink:to="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_019e64c7-5561-72f0-adc7-8db7b38137ca" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7b0e-9cf7-8e1b245be975" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_019e64c7-5561-72f0-adc7-8db7b38137ca" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7b0e-9cf7-8e1b245be975" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7b0e-9cf7-8e1b245be975_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7b0e-9cf7-8e1b245be975" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7b0e-9cf7-8e1b245be975_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7652-898d-3a2c236fbf75" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7b0e-9cf7-8e1b245be975" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7652-898d-3a2c236fbf75" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-79c0-be0a-74e7b7859b37" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7652-898d-3a2c236fbf75" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-79c0-be0a-74e7b7859b37" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-7f60-9aa0-d1a248803572" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7652-898d-3a2c236fbf75" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-7f60-9aa0-d1a248803572" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_019e64c7-5561-7ce1-92fb-e644e5b1e2b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7652-898d-3a2c236fbf75" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_019e64c7-5561-7ce1-92fb-e644e5b1e2b4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasesPortfolioSegmentMember_019e64c7-5561-733d-8941-71d93ed53985" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeasesPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7652-898d-3a2c236fbf75" xlink:to="loc_us-gaap_FinanceLeasesPortfolioSegmentMember_019e64c7-5561-733d-8941-71d93ed53985" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7f08-a2a1-5a40756cbf3c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_019e64c7-5561-72f0-adc7-8db7b38137ca" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7f08-a2a1-5a40756cbf3c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7f08-a2a1-5a40756cbf3c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7f08-a2a1-5a40756cbf3c" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7f08-a2a1-5a40756cbf3c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-78e9-9429-0482572c445a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7f08-a2a1-5a40756cbf3c" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-78e9-9429-0482572c445a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialLoanMember_019e64c7-5561-71f0-b273-d63469cf0228" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-78e9-9429-0482572c445a" xlink:to="loc_us-gaap_CommercialLoanMember_019e64c7-5561-71f0-b273-d63469cf0228" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateLoansMember_019e64c7-5561-7627-835f-5573e9eb7aa8" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-78e9-9429-0482572c445a" xlink:to="loc_msbi_CommercialRealEstateLoansMember_019e64c7-5561-7627-835f-5573e9eb7aa8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-75a4-8036-6fa1bb52ba7a" xlink:href="msbi-20260630.xsd#msbi_ConstructionAndLandDevelopmentLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-78e9-9429-0482572c445a" xlink:to="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-75a4-8036-6fa1bb52ba7a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ResidentialRealEstateLoanMember_019e64c7-5561-7e0b-b898-d4620e0355d3" xlink:href="msbi-20260630.xsd#msbi_ResidentialRealEstateLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-78e9-9429-0482572c445a" xlink:to="loc_msbi_ResidentialRealEstateLoanMember_019e64c7-5561-7e0b-b898-d4620e0355d3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerLoanMember_019e64c7-5561-7d05-888a-102d7496e24d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-78e9-9429-0482572c445a" xlink:to="loc_us-gaap_ConsumerLoanMember_019e64c7-5561-7d05-888a-102d7496e24d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRollForward_019e64c7-5561-7f74-80f2-6821fa8d6151" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_019e64c7-5561-7601-a479-d10ba75584b7" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRollForward_019e64c7-5561-7f74-80f2-6821fa8d6151" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_019e64c7-5561-7cd5-a66d-219ddb3ff2d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRollForward_019e64c7-5561-7f74-80f2-6821fa8d6151" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_019e64c7-5561-7cd5-a66d-219ddb3ff2d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal_019e64c7-5561-73a9-b28e-72ba73d02abe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRollForward_019e64c7-5561-7f74-80f2-6821fa8d6151" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal_019e64c7-5561-73a9-b28e-72ba73d02abe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_019e64c7-5561-7240-a158-b5b11650c5f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRollForward_019e64c7-5561-7f74-80f2-6821fa8d6151" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_019e64c7-5561-7240-a158-b5b11650c5f3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery_019e64c7-5561-7a54-a833-f75fcb196f36" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRollForward_019e64c7-5561-7f74-80f2-6821fa8d6151" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery_019e64c7-5561-7a54-a833-f75fcb196f36" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_019e64c7-5561-7df8-816e-1be9b137e8bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/LOANSRiskRatingDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#LOANSRiskRatingDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/LOANSRiskRatingDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7ced-9953-dd856414f0a3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7819-9ebe-d02e221ad371" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7ced-9953-dd856414f0a3" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7819-9ebe-d02e221ad371" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-78f4-aa47-cb563ddf26e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7819-9ebe-d02e221ad371" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-78f4-aa47-cb563ddf26e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-78f4-aa47-cb563ddf26e3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-78f4-aa47-cb563ddf26e3" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-78f4-aa47-cb563ddf26e3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-732d-9471-7727e87fd1c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-78f4-aa47-cb563ddf26e3" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-732d-9471-7727e87fd1c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ConsumerLoansAndEquipmentFinanceLoansAndLeasesMember_019e64c7-5561-708c-97f0-0e89ec68c69c" xlink:href="msbi-20260630.xsd#msbi_ConsumerLoansAndEquipmentFinanceLoansAndLeasesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-732d-9471-7727e87fd1c7" xlink:to="loc_msbi_ConsumerLoansAndEquipmentFinanceLoansAndLeasesMember_019e64c7-5561-708c-97f0-0e89ec68c69c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentAxis_019e64c7-5561-770c-bd33-7c794ef0c77a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InternalCreditAssessmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7819-9ebe-d02e221ad371" xlink:to="loc_us-gaap_InternalCreditAssessmentAxis_019e64c7-5561-770c-bd33-7c794ef0c77a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-770c-bd33-7c794ef0c77a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_019e64c7-5561-770c-bd33-7c794ef0c77a" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-770c-bd33-7c794ef0c77a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-7c05-a2fd-c82a80d0337b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_019e64c7-5561-770c-bd33-7c794ef0c77a" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-7c05-a2fd-c82a80d0337b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CreditRiskStateOneMember_019e64c7-5561-74b9-9d9d-337c40665fe2" xlink:href="msbi-20260630.xsd#msbi_CreditRiskStateOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-7c05-a2fd-c82a80d0337b" xlink:to="loc_msbi_CreditRiskStateOneMember_019e64c7-5561-74b9-9d9d-337c40665fe2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CreditRiskStateTwoMember_019e64c7-5561-746d-9373-8cf86b41ddb3" xlink:href="msbi-20260630.xsd#msbi_CreditRiskStateTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-7c05-a2fd-c82a80d0337b" xlink:to="loc_msbi_CreditRiskStateTwoMember_019e64c7-5561-746d-9373-8cf86b41ddb3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CreditRiskStateThreeMember_019e64c7-5561-7dac-ae13-3a369dc11e5a" xlink:href="msbi-20260630.xsd#msbi_CreditRiskStateThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-7c05-a2fd-c82a80d0337b" xlink:to="loc_msbi_CreditRiskStateThreeMember_019e64c7-5561-7dac-ae13-3a369dc11e5a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CreditRiskStateFourMember_019e64c7-5561-7e02-878b-16f1927a794b" xlink:href="msbi-20260630.xsd#msbi_CreditRiskStateFourMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-7c05-a2fd-c82a80d0337b" xlink:to="loc_msbi_CreditRiskStateFourMember_019e64c7-5561-7e02-878b-16f1927a794b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CreditRiskStateDefaultMember_019e64c7-5561-7b46-9c2f-46ac5dd286c7" xlink:href="msbi-20260630.xsd#msbi_CreditRiskStateDefaultMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-7c05-a2fd-c82a80d0337b" xlink:to="loc_msbi_CreditRiskStateDefaultMember_019e64c7-5561-7b46-9c2f-46ac5dd286c7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e64c7-5561-7ee9-abb1-56f17280a9e7" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7819-9ebe-d02e221ad371" xlink:to="loc_srt_RangeAxis_019e64c7-5561-7ee9-abb1-56f17280a9e7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e64c7-5561-7ee9-abb1-56f17280a9e7_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e64c7-5561-7ee9-abb1-56f17280a9e7" xlink:to="loc_srt_RangeMember_019e64c7-5561-7ee9-abb1-56f17280a9e7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e64c7-5561-7ae2-af52-cc11da996d08" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e64c7-5561-7ee9-abb1-56f17280a9e7" xlink:to="loc_srt_RangeMember_019e64c7-5561-7ae2-af52-cc11da996d08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019e64c7-5561-75e2-96e6-c0218f539a76" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e64c7-5561-7ae2-af52-cc11da996d08" xlink:to="loc_srt_MinimumMember_019e64c7-5561-75e2-96e6-c0218f539a76" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e64c7-5561-7cac-96fd-6c20160e68fe" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e64c7-5561-7ae2-af52-cc11da996d08" xlink:to="loc_srt_MaximumMember_019e64c7-5561-7cac-96fd-6c20160e68fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableThresholdPeriodPastDue_019e64c7-5561-7a38-9c7e-0b2157a7bb14" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableThresholdPeriodPastDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7ced-9953-dd856414f0a3" xlink:to="loc_us-gaap_FinancingReceivableThresholdPeriodPastDue_019e64c7-5561-7a38-9c7e-0b2157a7bb14" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/LOANSNonaccrualDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#LOANSNonaccrualDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/LOANSNonaccrualDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableImpairedLineItems_019e64c7-5561-7216-bfa0-f0654b90be6b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableImpairedLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7559-a152-55115ff91496" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_019e64c7-5561-7216-bfa0-f0654b90be6b" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7559-a152-55115ff91496" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7df2-a071-6c4052c0cb42" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7559-a152-55115ff91496" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7df2-a071-6c4052c0cb42" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7df2-a071-6c4052c0cb42_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7df2-a071-6c4052c0cb42" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7df2-a071-6c4052c0cb42_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7131-9b3d-60350c89b986" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7df2-a071-6c4052c0cb42" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7131-9b3d-60350c89b986" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-7f6d-bb41-ddcee74c8501" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7131-9b3d-60350c89b986" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-7f6d-bb41-ddcee74c8501" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-7482-8991-2f43e5046b77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7131-9b3d-60350c89b986" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-7482-8991-2f43e5046b77" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_019e64c7-5561-7bb5-9169-1d9b6e59a9ae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7131-9b3d-60350c89b986" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_019e64c7-5561-7bb5-9169-1d9b6e59a9ae" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasesPortfolioSegmentMember_019e64c7-5561-71ad-885e-277018c40e8a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeasesPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7131-9b3d-60350c89b986" xlink:to="loc_us-gaap_FinanceLeasesPortfolioSegmentMember_019e64c7-5561-71ad-885e-277018c40e8a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-753f-a814-544f21ce7954" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7559-a152-55115ff91496" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-753f-a814-544f21ce7954" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-753f-a814-544f21ce7954_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-753f-a814-544f21ce7954" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-753f-a814-544f21ce7954_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7497-b05c-46e2fbd9cc19" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-753f-a814-544f21ce7954" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7497-b05c-46e2fbd9cc19" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialLoanMember_019e64c7-5561-7031-9794-23112ddbdde7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7497-b05c-46e2fbd9cc19" xlink:to="loc_us-gaap_CommercialLoanMember_019e64c7-5561-7031-9794-23112ddbdde7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-72d1-b8b1-38fcbd6706d3" xlink:href="msbi-20260630.xsd#msbi_CommercialOtherLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7497-b05c-46e2fbd9cc19" xlink:to="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-72d1-b8b1-38fcbd6706d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019e64c7-5561-7714-a0e3-85b8cfc7e538" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateNonOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7497-b05c-46e2fbd9cc19" xlink:to="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019e64c7-5561-7714-a0e3-85b8cfc7e538" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019e64c7-5561-7795-a976-16d9167128ee" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7497-b05c-46e2fbd9cc19" xlink:to="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019e64c7-5561-7795-a976-16d9167128ee" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_019e64c7-5561-70fe-a23e-a0a8e6d2fd6f" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7497-b05c-46e2fbd9cc19" xlink:to="loc_srt_MultifamilyMember_019e64c7-5561-70fe-a23e-a0a8e6d2fd6f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FarmlandLoansMember_019e64c7-5561-7c81-a783-c6033d2a9569" xlink:href="msbi-20260630.xsd#msbi_FarmlandLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7497-b05c-46e2fbd9cc19" xlink:to="loc_msbi_FarmlandLoansMember_019e64c7-5561-7c81-a783-c6033d2a9569" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-7ae8-954a-83172607ef53" xlink:href="msbi-20260630.xsd#msbi_ConstructionAndLandDevelopmentLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7497-b05c-46e2fbd9cc19" xlink:to="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-7ae8-954a-83172607ef53" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-7134-804b-abe13eb20228" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7497-b05c-46e2fbd9cc19" xlink:to="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-7134-804b-abe13eb20228" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-7ce8-902b-813bb32d71f2" xlink:href="msbi-20260630.xsd#msbi_OtherResidentialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7497-b05c-46e2fbd9cc19" xlink:to="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-7ce8-902b-813bb32d71f2" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerLoanMember_019e64c7-5561-7ce6-9a58-046aabbe6ae1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7497-b05c-46e2fbd9cc19" xlink:to="loc_us-gaap_ConsumerLoanMember_019e64c7-5561-7ce6-9a58-046aabbe6ae1" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonaccrualStatusAbstract_019e64c7-5561-7dc3-8a53-4596155e936e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonaccrualStatusAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_019e64c7-5561-7216-bfa0-f0654b90be6b" xlink:to="loc_us-gaap_NonaccrualStatusAbstract_019e64c7-5561-7dc3-8a53-4596155e936e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FinancingReceivableNonaccrualWithAllowance_019e64c7-5561-7492-a670-502f2ba6c68e" xlink:href="msbi-20260630.xsd#msbi_FinancingReceivableNonaccrualWithAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonaccrualStatusAbstract_019e64c7-5561-7dc3-8a53-4596155e936e" xlink:to="loc_msbi_FinancingReceivableNonaccrualWithAllowance_019e64c7-5561-7492-a670-502f2ba6c68e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrualNoAllowance_019e64c7-5561-7f63-b36a-572310f0996d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrualNoAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonaccrualStatusAbstract_019e64c7-5561-7dc3-8a53-4596155e936e" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrualNoAllowance_019e64c7-5561-7f63-b36a-572310f0996d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrual_019e64c7-5561-70bd-9a10-327908f48bfb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrual"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonaccrualStatusAbstract_019e64c7-5561-7dc3-8a53-4596155e936e" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrual_019e64c7-5561-70bd-9a10-327908f48bfb" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/LOANSCollateralDependentLoansDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#LOANSCollateralDependentLoansDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/LOANSCollateralDependentLoansDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-7512-8f18-30de6baf1397" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7917-a6c2-7e743698539d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-7512-8f18-30de6baf1397" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7917-a6c2-7e743698539d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7ca9-b133-ed285e7604f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7917-a6c2-7e743698539d" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7ca9-b133-ed285e7604f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7ca9-b133-ed285e7604f7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7ca9-b133-ed285e7604f7" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7ca9-b133-ed285e7604f7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7d45-bab3-63fffe7651c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7ca9-b133-ed285e7604f7" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7d45-bab3-63fffe7651c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-7226-920c-8135ce2fa8a0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7d45-bab3-63fffe7651c9" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-7226-920c-8135ce2fa8a0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_019faf6e-eac4-748d-a307-16ad832be036" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7d45-bab3-63fffe7651c9" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_019faf6e-eac4-748d-a307-16ad832be036" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7bb9-95fd-19a8d5d06520" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7917-a6c2-7e743698539d" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7bb9-95fd-19a8d5d06520" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7bb9-95fd-19a8d5d06520_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7bb9-95fd-19a8d5d06520" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7bb9-95fd-19a8d5d06520_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-74b8-b9ec-6c660a778b69" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7bb9-95fd-19a8d5d06520" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-74b8-b9ec-6c660a778b69" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialLoanMember_019e64c7-5561-7a44-8c78-db1dd8aefab9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-74b8-b9ec-6c660a778b69" xlink:to="loc_us-gaap_CommercialLoanMember_019e64c7-5561-7a44-8c78-db1dd8aefab9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-7ef5-b071-e9d1f0808b58" xlink:href="msbi-20260630.xsd#msbi_CommercialOtherLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-74b8-b9ec-6c660a778b69" xlink:to="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-7ef5-b071-e9d1f0808b58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019e64c7-5561-7051-ad7e-79877908e437" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateNonOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-74b8-b9ec-6c660a778b69" xlink:to="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019e64c7-5561-7051-ad7e-79877908e437" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019e64c7-5561-7c50-bdc7-dd2e2cefdc0c" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-74b8-b9ec-6c660a778b69" xlink:to="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019e64c7-5561-7c50-bdc7-dd2e2cefdc0c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_019e64c7-5561-7ca7-a929-c6b5097aec2d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-74b8-b9ec-6c660a778b69" xlink:to="loc_srt_MultifamilyMember_019e64c7-5561-7ca7-a929-c6b5097aec2d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FarmlandLoansMember_019e64c7-5561-753d-87f0-4fd5a69b2964" xlink:href="msbi-20260630.xsd#msbi_FarmlandLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-74b8-b9ec-6c660a778b69" xlink:to="loc_msbi_FarmlandLoansMember_019e64c7-5561-753d-87f0-4fd5a69b2964" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019f65a8-b927-7e40-9ba9-3c9ec13d2b73" xlink:href="msbi-20260630.xsd#msbi_ConstructionAndLandDevelopmentLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-74b8-b9ec-6c660a778b69" xlink:to="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019f65a8-b927-7e40-9ba9-3c9ec13d2b73" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateLoanMember_019faf6e-eac4-753b-9788-10a75b98ce4c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-74b8-b9ec-6c660a778b69" xlink:to="loc_us-gaap_RealEstateLoanMember_019faf6e-eac4-753b-9788-10a75b98ce4c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherResidentialLoansMember_019faf6e-eac4-7ae6-878d-96936d950dac" xlink:href="msbi-20260630.xsd#msbi_OtherResidentialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-74b8-b9ec-6c660a778b69" xlink:to="loc_msbi_OtherResidentialLoansMember_019faf6e-eac4-7ae6-878d-96936d950dac" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralAxis_019e64c7-5561-7500-bc4d-b1a3d70aaeb6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7917-a6c2-7e743698539d" xlink:to="loc_us-gaap_CollateralAxis_019e64c7-5561-7500-bc4d-b1a3d70aaeb6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_019e64c7-5561-7500-bc4d-b1a3d70aaeb6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CollateralAxis_019e64c7-5561-7500-bc4d-b1a3d70aaeb6" xlink:to="loc_us-gaap_CollateralDomain_019e64c7-5561-7500-bc4d-b1a3d70aaeb6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_019e64c7-5561-769d-b469-748572ec9988" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CollateralAxis_019e64c7-5561-7500-bc4d-b1a3d70aaeb6" xlink:to="loc_us-gaap_CollateralDomain_019e64c7-5561-769d-b469-748572ec9988" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateMember_019e64c7-5561-7bb2-9cb7-758f4ba5498f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_019e64c7-5561-769d-b469-748572ec9988" xlink:to="loc_us-gaap_RealEstateMember_019e64c7-5561-7bb2-9cb7-758f4ba5498f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_BlanketLienMember_019e64c7-5561-7d49-bcd2-2fe54f6e9423" xlink:href="msbi-20260630.xsd#msbi_BlanketLienMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_019e64c7-5561-769d-b469-748572ec9988" xlink:to="loc_msbi_BlanketLienMember_019e64c7-5561-7d49-bcd2-2fe54f6e9423" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquipmentMember_019faf6e-eac4-7b17-9c21-3e6542429c24" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_019e64c7-5561-769d-b469-748572ec9988" xlink:to="loc_us-gaap_EquipmentMember_019faf6e-eac4-7b17-9c21-3e6542429c24" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CollateralDependentLoans_019e64c7-5561-75da-bba8-1892333daf96" xlink:href="msbi-20260630.xsd#msbi_CollateralDependentLoans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-7512-8f18-30de6baf1397" xlink:to="loc_msbi_CollateralDependentLoans_019e64c7-5561-75da-bba8-1892333daf96" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/LOANSAgingStatusofRecordedInvestmentDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#LOANSAgingStatusofRecordedInvestmentDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/LOANSAgingStatusofRecordedInvestmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019e64c7-5561-798d-a863-bf1957f44d81" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-770e-a501-e06da542c939" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019e64c7-5561-798d-a863-bf1957f44d81" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-770e-a501-e06da542c939" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7978-83ff-1b1d99388788" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-770e-a501-e06da542c939" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7978-83ff-1b1d99388788" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7978-83ff-1b1d99388788_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7978-83ff-1b1d99388788" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7978-83ff-1b1d99388788_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7e84-bb21-acf64fe47dc1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7978-83ff-1b1d99388788" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7e84-bb21-acf64fe47dc1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-7b3d-88aa-cf73624719b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7e84-bb21-acf64fe47dc1" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-7b3d-88aa-cf73624719b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-753b-b160-3fc955cf4139" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7e84-bb21-acf64fe47dc1" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-753b-b160-3fc955cf4139" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_019e64c7-5561-7a49-b157-be6010c34f5d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7e84-bb21-acf64fe47dc1" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_019e64c7-5561-7a49-b157-be6010c34f5d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasesPortfolioSegmentMember_019e64c7-5561-72ff-b731-8a0d2a6cdd08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeasesPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7e84-bb21-acf64fe47dc1" xlink:to="loc_us-gaap_FinanceLeasesPortfolioSegmentMember_019e64c7-5561-72ff-b731-8a0d2a6cdd08" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7262-91b6-29b1c1bf5366" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-770e-a501-e06da542c939" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7262-91b6-29b1c1bf5366" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7262-91b6-29b1c1bf5366_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7262-91b6-29b1c1bf5366" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7262-91b6-29b1c1bf5366_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-75b7-a958-e102b35ec708" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7262-91b6-29b1c1bf5366" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-75b7-a958-e102b35ec708" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialLoanMember_019e64c7-5561-75ed-8ff6-b3b9db7e0e7f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-75b7-a958-e102b35ec708" xlink:to="loc_us-gaap_CommercialLoanMember_019e64c7-5561-75ed-8ff6-b3b9db7e0e7f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-77ce-bb55-5de60b78a741" xlink:href="msbi-20260630.xsd#msbi_CommercialOtherLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-75b7-a958-e102b35ec708" xlink:to="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-77ce-bb55-5de60b78a741" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019e64c7-5561-7aa1-b945-e029f801c7ed" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateNonOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-75b7-a958-e102b35ec708" xlink:to="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019e64c7-5561-7aa1-b945-e029f801c7ed" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019e64c7-5561-7009-b1fb-298aa85704da" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-75b7-a958-e102b35ec708" xlink:to="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019e64c7-5561-7009-b1fb-298aa85704da" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_019e64c7-5561-7490-b61c-3938df31be8d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-75b7-a958-e102b35ec708" xlink:to="loc_srt_MultifamilyMember_019e64c7-5561-7490-b61c-3938df31be8d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FarmlandLoansMember_019e64c7-5561-726d-9ab2-aa4f64c1e82b" xlink:href="msbi-20260630.xsd#msbi_FarmlandLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-75b7-a958-e102b35ec708" xlink:to="loc_msbi_FarmlandLoansMember_019e64c7-5561-726d-9ab2-aa4f64c1e82b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-7a38-bc9a-d22285c57714" xlink:href="msbi-20260630.xsd#msbi_ConstructionAndLandDevelopmentLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-75b7-a958-e102b35ec708" xlink:to="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-7a38-bc9a-d22285c57714" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-7c85-8a8d-1cbe0deacae5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-75b7-a958-e102b35ec708" xlink:to="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-7c85-8a8d-1cbe0deacae5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-7015-8745-c6c2ad6f5147" xlink:href="msbi-20260630.xsd#msbi_OtherResidentialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-75b7-a958-e102b35ec708" xlink:to="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-7015-8745-c6c2ad6f5147" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerLoanMember_019e64c7-5561-7fe6-a20e-582433003711" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-75b7-a958-e102b35ec708" xlink:to="loc_us-gaap_ConsumerLoanMember_019e64c7-5561-7fe6-a20e-582433003711" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherConsumerLoansMember_019e64c7-5561-7714-a297-8b6484c9ae02" xlink:href="msbi-20260630.xsd#msbi_OtherConsumerLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-75b7-a958-e102b35ec708" xlink:to="loc_msbi_OtherConsumerLoansMember_019e64c7-5561-7714-a297-8b6484c9ae02" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e64c7-5561-7d3b-9204-fb259dbac6c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-770e-a501-e06da542c939" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e64c7-5561-7d3b-9204-fb259dbac6c9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7d3b-9204-fb259dbac6c9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e64c7-5561-7d3b-9204-fb259dbac6c9" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7d3b-9204-fb259dbac6c9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7a69-a494-610fe33890d9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e64c7-5561-7d3b-9204-fb259dbac6c9" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7a69-a494-610fe33890d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetNotPastDueMember_019e64c7-5561-70cf-9ee6-caff1dd602f9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialAssetNotPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7a69-a494-610fe33890d9" xlink:to="loc_us-gaap_FinancialAssetNotPastDueMember_019e64c7-5561-70cf-9ee6-caff1dd602f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivables30To59DaysPastDueMember_019e64c7-5561-73a3-917b-d65d402d8de1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivables30To59DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7a69-a494-610fe33890d9" xlink:to="loc_us-gaap_FinancingReceivables30To59DaysPastDueMember_019e64c7-5561-73a3-917b-d65d402d8de1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivables60To89DaysPastDueMember_019e64c7-5561-720c-a931-2aa6eda4cf20" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivables60To89DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7a69-a494-610fe33890d9" xlink:to="loc_us-gaap_FinancingReceivables60To89DaysPastDueMember_019e64c7-5561-720c-a931-2aa6eda4cf20" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_019e64c7-5561-78fe-b81c-3abb70d9ed1d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7a69-a494-610fe33890d9" xlink:to="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_019e64c7-5561-78fe-b81c-3abb70d9ed1d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetPastDueMember_019e64c7-5561-7f81-b124-98eecc54aed1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialAssetPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7a69-a494-610fe33890d9" xlink:to="loc_us-gaap_FinancialAssetPastDueMember_019e64c7-5561-7f81-b124-98eecc54aed1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_019e64c7-5561-7b18-814e-31891d708676" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentPerformanceStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-770e-a501-e06da542c939" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_019e64c7-5561-7b18-814e-31891d708676" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_019e64c7-5561-7b18-814e-31891d708676_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentPerformanceStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_019e64c7-5561-7b18-814e-31891d708676" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_019e64c7-5561-7b18-814e-31891d708676_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_019e64c7-5561-71ff-9669-85f90334dafa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentPerformanceStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_019e64c7-5561-7b18-814e-31891d708676" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_019e64c7-5561-71ff-9669-85f90334dafa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformingFinancingReceivableMember_019e64c7-5561-750f-b2b8-db784e904b7f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PerformingFinancingReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_019e64c7-5561-71ff-9669-85f90334dafa" xlink:to="loc_us-gaap_PerformingFinancingReceivableMember_019e64c7-5561-750f-b2b8-db784e904b7f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonperformingFinancingReceivableMember_019e64c7-5561-7cca-8b42-45f4d451d488" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonperformingFinancingReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_019e64c7-5561-71ff-9669-85f90334dafa" xlink:to="loc_us-gaap_NonperformingFinancingReceivableMember_019e64c7-5561-7cca-8b42-45f4d451d488" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e64c7-5561-70f7-a76d-fec9e499c25c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019e64c7-5561-798d-a863-bf1957f44d81" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e64c7-5561-70f7-a76d-fec9e499c25c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrual_019e64c7-5561-7f4d-aa20-80bc2d041e5e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrual"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019e64c7-5561-798d-a863-bf1957f44d81" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrual_019e64c7-5561-7f4d-aa20-80bc2d041e5e" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/LOANSLoanRestructuringDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#LOANSLoanRestructuringDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/LOANSLoanRestructuringDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-742d-bd1b-b171853de7dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7ef1-9e30-43c8452c83f9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-742d-bd1b-b171853de7dd" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7ef1-9e30-43c8452c83f9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-72dd-b6a5-fecd59f06425" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7ef1-9e30-43c8452c83f9" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-72dd-b6a5-fecd59f06425" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-72dd-b6a5-fecd59f06425_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-72dd-b6a5-fecd59f06425" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-72dd-b6a5-fecd59f06425_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-725d-8c6c-38c99b997630" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-72dd-b6a5-fecd59f06425" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-725d-8c6c-38c99b997630" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-7a78-bdba-57ba43fd3fea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-725d-8c6c-38c99b997630" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-7a78-bdba-57ba43fd3fea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-7def-998b-d5fdbff757be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-725d-8c6c-38c99b997630" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-7def-998b-d5fdbff757be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7e46-bf9c-d1adc1ef58e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-7ef1-9e30-43c8452c83f9" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7e46-bf9c-d1adc1ef58e8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7e46-bf9c-d1adc1ef58e8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7e46-bf9c-d1adc1ef58e8" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7e46-bf9c-d1adc1ef58e8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7704-838d-8990fc01ee3b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7e46-bf9c-d1adc1ef58e8" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7704-838d-8990fc01ee3b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialLoanMember_019e64c7-5561-7f03-80de-ca31b54ebfff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7704-838d-8990fc01ee3b" xlink:to="loc_us-gaap_CommercialLoanMember_019e64c7-5561-7f03-80de-ca31b54ebfff" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-7966-bdae-d58e8f52d686" xlink:href="msbi-20260630.xsd#msbi_CommercialOtherLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7704-838d-8990fc01ee3b" xlink:to="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-7966-bdae-d58e8f52d686" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019f65aa-0d93-734d-a5e3-449d4216340b" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateNonOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7704-838d-8990fc01ee3b" xlink:to="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019f65aa-0d93-734d-a5e3-449d4216340b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019ed8fe-1dac-7d8b-b3f5-4ea214c249f2" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7704-838d-8990fc01ee3b" xlink:to="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019ed8fe-1dac-7d8b-b3f5-4ea214c249f2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_019f6bbd-e4ac-756c-a331-87ff8ef3af36" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7704-838d-8990fc01ee3b" xlink:to="loc_srt_MultifamilyMember_019f6bbd-e4ac-756c-a331-87ff8ef3af36" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FarmlandLoansMember_019e64c7-5561-7fa4-89de-9b85f9e675dc" xlink:href="msbi-20260630.xsd#msbi_FarmlandLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7704-838d-8990fc01ee3b" xlink:to="loc_msbi_FarmlandLoansMember_019e64c7-5561-7fa4-89de-9b85f9e675dc" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-7108-ac3e-6facf25e4079" xlink:href="msbi-20260630.xsd#msbi_ConstructionAndLandDevelopmentLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7704-838d-8990fc01ee3b" xlink:to="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-7108-ac3e-6facf25e4079" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-7d76-905d-1c3fa9e2a40f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7704-838d-8990fc01ee3b" xlink:to="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-7d76-905d-1c3fa9e2a40f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-711f-89b3-5ba27892bba0" xlink:href="msbi-20260630.xsd#msbi_OtherResidentialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7704-838d-8990fc01ee3b" xlink:to="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-711f-89b3-5ba27892bba0" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_019e64c7-5561-75a6-8975-fbe6a1bfa413" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-742d-bd1b-b171853de7dd" xlink:to="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_019e64c7-5561-75a6-8975-fbe6a1bfa413" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FinancingReceivableModifiedInPeriodNumberOfContracts_019e64c7-5561-7bad-b43c-b398990da54f" xlink:href="msbi-20260630.xsd#msbi_FinancingReceivableModifiedInPeriodNumberOfContracts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-742d-bd1b-b171853de7dd" xlink:to="loc_msbi_FinancingReceivableModifiedInPeriodNumberOfContracts_019e64c7-5561-7bad-b43c-b398990da54f" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/LOANSModifiedFinancingReceivableDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#LOANSModifiedFinancingReceivableDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/LOANSModifiedFinancingReceivableDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-7007-8045-047f1092a08b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-714e-989c-1b51efb000c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-7007-8045-047f1092a08b" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-714e-989c-1b51efb000c2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-787c-bc06-66f55d9f2093" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-714e-989c-1b51efb000c2" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-787c-bc06-66f55d9f2093" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-787c-bc06-66f55d9f2093_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-787c-bc06-66f55d9f2093" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-787c-bc06-66f55d9f2093_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7a06-be33-7bb89794a1c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-787c-bc06-66f55d9f2093" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7a06-be33-7bb89794a1c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-7b5a-800a-bbfd9850f321" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7a06-be33-7bb89794a1c5" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-7b5a-800a-bbfd9850f321" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-7235-8b07-42eacf7d9e90" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7a06-be33-7bb89794a1c5" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-7235-8b07-42eacf7d9e90" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7b8b-bc87-7e237bd8d145" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-714e-989c-1b51efb000c2" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7b8b-bc87-7e237bd8d145" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7b8b-bc87-7e237bd8d145_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7b8b-bc87-7e237bd8d145" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7b8b-bc87-7e237bd8d145_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7ec5-9bfa-e6da62dc5e15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7b8b-bc87-7e237bd8d145" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7ec5-9bfa-e6da62dc5e15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialLoanMember_019e64c7-5561-79ef-809d-5c866dcf6136" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7ec5-9bfa-e6da62dc5e15" xlink:to="loc_us-gaap_CommercialLoanMember_019e64c7-5561-79ef-809d-5c866dcf6136" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-71c2-99cf-2bc9b5433395" xlink:href="msbi-20260630.xsd#msbi_CommercialOtherLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7ec5-9bfa-e6da62dc5e15" xlink:to="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-71c2-99cf-2bc9b5433395" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019f65ae-9052-7969-8f13-38e3c1c0e68a" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateNonOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7ec5-9bfa-e6da62dc5e15" xlink:to="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019f65ae-9052-7969-8f13-38e3c1c0e68a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_019f6bbf-aea0-775d-bd39-48fa40c831a4" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7ec5-9bfa-e6da62dc5e15" xlink:to="loc_srt_MultifamilyMember_019f6bbf-aea0-775d-bd39-48fa40c831a4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019f65b0-9afb-72cc-956b-80f23f58c6ab" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7ec5-9bfa-e6da62dc5e15" xlink:to="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019f65b0-9afb-72cc-956b-80f23f58c6ab" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FarmlandLoansMember_019e64c7-5561-7e03-be71-db54d7a065f9" xlink:href="msbi-20260630.xsd#msbi_FarmlandLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7ec5-9bfa-e6da62dc5e15" xlink:to="loc_msbi_FarmlandLoansMember_019e64c7-5561-7e03-be71-db54d7a065f9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-7046-a352-60c512d85d67" xlink:href="msbi-20260630.xsd#msbi_ConstructionAndLandDevelopmentLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7ec5-9bfa-e6da62dc5e15" xlink:to="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-7046-a352-60c512d85d67" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-7dcb-9aef-6af8d920cef7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7ec5-9bfa-e6da62dc5e15" xlink:to="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-7dcb-9aef-6af8d920cef7" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-7c43-8251-69e19eca094d" xlink:href="msbi-20260630.xsd#msbi_OtherResidentialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7ec5-9bfa-e6da62dc5e15" xlink:to="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-7c43-8251-69e19eca094d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationAxis_019e64c7-5561-79a2-b26f-625937092b24" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoanRestructuringModificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e64c7-5561-714e-989c-1b51efb000c2" xlink:to="loc_us-gaap_LoanRestructuringModificationAxis_019e64c7-5561-79a2-b26f-625937092b24" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_019e64c7-5561-79a2-b26f-625937092b24_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_019e64c7-5561-79a2-b26f-625937092b24" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_019e64c7-5561-79a2-b26f-625937092b24_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_019e64c7-5561-77fd-ac22-c8ddcce98b21" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_019e64c7-5561-79a2-b26f-625937092b24" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_019e64c7-5561-77fd-ac22-c8ddcce98b21" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentDeferralMember_019f6bbe-a6fe-7c9a-be51-549ef91faedb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentDeferralMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019e64c7-5561-77fd-ac22-c8ddcce98b21" xlink:to="loc_us-gaap_PaymentDeferralMember_019f6bbe-a6fe-7c9a-be51-549ef91faedb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtendedMaturityMember_019e64c7-5561-7e37-a806-4c8fe4512a15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ExtendedMaturityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019e64c7-5561-77fd-ac22-c8ddcce98b21" xlink:to="loc_us-gaap_ExtendedMaturityMember_019e64c7-5561-7e37-a806-4c8fe4512a15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualInterestRateReductionMember_019e64c7-5561-7528-8925-5f1909cbd3e7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractualInterestRateReductionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019e64c7-5561-77fd-ac22-c8ddcce98b21" xlink:to="loc_us-gaap_ContractualInterestRateReductionMember_019e64c7-5561-7528-8925-5f1909cbd3e7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_MaturityDeferralAndInterestRateReductionMember_019f65b5-c517-76e0-9928-28f0c3cdae8f" xlink:href="msbi-20260630.xsd#msbi_MaturityDeferralAndInterestRateReductionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019e64c7-5561-77fd-ac22-c8ddcce98b21" xlink:to="loc_msbi_MaturityDeferralAndInterestRateReductionMember_019f65b5-c517-76e0-9928-28f0c3cdae8f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ExtendedMaturityAndMaturityDeferralMember_019f65b5-c517-7a14-9ec3-2092dec2bba4" xlink:href="msbi-20260630.xsd#msbi_ExtendedMaturityAndMaturityDeferralMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019e64c7-5561-77fd-ac22-c8ddcce98b21" xlink:to="loc_msbi_ExtendedMaturityAndMaturityDeferralMember_019f65b5-c517-7a14-9ec3-2092dec2bba4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_019e64c7-5561-701d-8663-f6933048fdb6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-7007-8045-047f1092a08b" xlink:to="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_019e64c7-5561-701d-8663-f6933048fdb6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesPercent_019e64c7-5561-7b42-afc9-f26366a4fde8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e64c7-5561-7007-8045-047f1092a08b" xlink:to="loc_us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesPercent_019e64c7-5561-7b42-afc9-f26366a4fde8" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/LOANSScheduleofPerformanceofModifiedLoansDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#LOANSScheduleofPerformanceofModifiedLoansDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/LOANSScheduleofPerformanceofModifiedLoansDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-72c8-8d14-2a414cc8349e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7b7d-9c8b-0ef95f9345a8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-72c8-8d14-2a414cc8349e" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7b7d-9c8b-0ef95f9345a8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-71f3-a0f7-5f6cd49630b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7b7d-9c8b-0ef95f9345a8" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-71f3-a0f7-5f6cd49630b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-71f3-a0f7-5f6cd49630b5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-71f3-a0f7-5f6cd49630b5" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-71f3-a0f7-5f6cd49630b5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-717d-b4c2-c390911bcae0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-71f3-a0f7-5f6cd49630b5" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-717d-b4c2-c390911bcae0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-7fab-9954-4e60d59d98f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-717d-b4c2-c390911bcae0" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-7fab-9954-4e60d59d98f5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-7e0d-a68c-b057f7c5b418" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-717d-b4c2-c390911bcae0" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-7e0d-a68c-b057f7c5b418" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_019f65bf-cff9-7d20-9f44-2a48f7c69319" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-717d-b4c2-c390911bcae0" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_019f65bf-cff9-7d20-9f44-2a48f7c69319" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasesPortfolioSegmentMember_019f65bf-cff9-7d89-8913-f2a6d514ebdc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeasesPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-717d-b4c2-c390911bcae0" xlink:to="loc_us-gaap_FinanceLeasesPortfolioSegmentMember_019f65bf-cff9-7d89-8913-f2a6d514ebdc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-707b-8fd3-3f4d6cc22215" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7b7d-9c8b-0ef95f9345a8" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-707b-8fd3-3f4d6cc22215" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-707b-8fd3-3f4d6cc22215_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-707b-8fd3-3f4d6cc22215" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-707b-8fd3-3f4d6cc22215_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7aab-a585-03b356fd0196" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-707b-8fd3-3f4d6cc22215" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7aab-a585-03b356fd0196" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialLoanMember_019e64c7-5561-7971-82ba-405f83b87b9a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7aab-a585-03b356fd0196" xlink:to="loc_us-gaap_CommercialLoanMember_019e64c7-5561-7971-82ba-405f83b87b9a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-72b2-b615-c185edeea1e3" xlink:href="msbi-20260630.xsd#msbi_CommercialOtherLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7aab-a585-03b356fd0196" xlink:to="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-72b2-b615-c185edeea1e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019e64c7-5561-7307-9157-645b4cd1abb4" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateNonOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7aab-a585-03b356fd0196" xlink:to="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019e64c7-5561-7307-9157-645b4cd1abb4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019f65be-b643-74fe-95be-f1c12bdd183c" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7aab-a585-03b356fd0196" xlink:to="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019f65be-b643-74fe-95be-f1c12bdd183c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_019f6bc0-b813-7962-b1dd-2a7bfbf1e8eb" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7aab-a585-03b356fd0196" xlink:to="loc_srt_MultifamilyMember_019f6bc0-b813-7962-b1dd-2a7bfbf1e8eb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FarmlandLoansMember_019e64c7-5561-765f-8d2a-03eed82d9113" xlink:href="msbi-20260630.xsd#msbi_FarmlandLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7aab-a585-03b356fd0196" xlink:to="loc_msbi_FarmlandLoansMember_019e64c7-5561-765f-8d2a-03eed82d9113" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-7b36-92ea-2cb0017fbde6" xlink:href="msbi-20260630.xsd#msbi_ConstructionAndLandDevelopmentLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7aab-a585-03b356fd0196" xlink:to="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-7b36-92ea-2cb0017fbde6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-721a-a120-ed8093c11646" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7aab-a585-03b356fd0196" xlink:to="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-721a-a120-ed8093c11646" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-79c0-8220-130dcd38cea4" xlink:href="msbi-20260630.xsd#msbi_OtherResidentialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7aab-a585-03b356fd0196" xlink:to="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-79c0-8220-130dcd38cea4" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerLoanMember_019f65bf-cff9-7d64-8c42-b9c21b500843" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7aab-a585-03b356fd0196" xlink:to="loc_us-gaap_ConsumerLoanMember_019f65bf-cff9-7d64-8c42-b9c21b500843" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e64c7-5561-79f4-aa3c-6700b48be829" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7b7d-9c8b-0ef95f9345a8" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e64c7-5561-79f4-aa3c-6700b48be829" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-79f4-aa3c-6700b48be829_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e64c7-5561-79f4-aa3c-6700b48be829" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-79f4-aa3c-6700b48be829_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7b77-a32d-d47b967fcacc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e64c7-5561-79f4-aa3c-6700b48be829" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7b77-a32d-d47b967fcacc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivables30To59DaysPastDueMember_019e64c7-5561-71fa-aa52-3421d57ff556" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivables30To59DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7b77-a32d-d47b967fcacc" xlink:to="loc_us-gaap_FinancingReceivables30To59DaysPastDueMember_019e64c7-5561-71fa-aa52-3421d57ff556" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivables60To89DaysPastDueMember_019e64c7-5561-751c-8967-2cfed4c998fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivables60To89DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7b77-a32d-d47b967fcacc" xlink:to="loc_us-gaap_FinancingReceivables60To89DaysPastDueMember_019e64c7-5561-751c-8967-2cfed4c998fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_019e64c7-5561-722a-bcc8-e7e5509e00f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7b77-a32d-d47b967fcacc" xlink:to="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_019e64c7-5561-722a-bcc8-e7e5509e00f2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetPastDueMember_019e64c7-5561-7e8a-a62c-08d4ab6ff5d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialAssetPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7b77-a32d-d47b967fcacc" xlink:to="loc_us-gaap_FinancialAssetPastDueMember_019e64c7-5561-7e8a-a62c-08d4ab6ff5d0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetNotPastDueMember_019e64c7-5561-76c3-b82e-302f66c2226f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialAssetNotPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e64c7-5561-7b77-a32d-d47b967fcacc" xlink:to="loc_us-gaap_FinancialAssetNotPastDueMember_019e64c7-5561-76c3-b82e-302f66c2226f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModifiedPast12Months_019e64c7-5561-775b-a3af-8be6c1ae51f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableModifiedPast12Months"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-72c8-8d14-2a414cc8349e" xlink:to="loc_us-gaap_FinancingReceivableModifiedPast12Months_019e64c7-5561-775b-a3af-8be6c1ae51f8" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/LOANSRiskCategoryDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#LOANSRiskCategoryDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/LOANSRiskCategoryDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7836-8aa7-4bdc81f4d82a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7731-97ec-c1fbb28e238e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7836-8aa7-4bdc81f4d82a" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7731-97ec-c1fbb28e238e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7f62-8846-9ca853008630" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7731-97ec-c1fbb28e238e" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7f62-8846-9ca853008630" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7f62-8846-9ca853008630_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7f62-8846-9ca853008630" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7f62-8846-9ca853008630_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7646-b2d7-12f3a965a405" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7f62-8846-9ca853008630" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7646-b2d7-12f3a965a405" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialLoanMember_019e64c7-5561-7e95-a2f5-c31575ae3a8c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7646-b2d7-12f3a965a405" xlink:to="loc_us-gaap_CommercialLoanMember_019e64c7-5561-7e95-a2f5-c31575ae3a8c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-7754-9cfa-2b3e77a345ed" xlink:href="msbi-20260630.xsd#msbi_CommercialOtherLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7646-b2d7-12f3a965a405" xlink:to="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-7754-9cfa-2b3e77a345ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019e64c7-5561-711e-b05a-280077b1f62a" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateNonOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7646-b2d7-12f3a965a405" xlink:to="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019e64c7-5561-711e-b05a-280077b1f62a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019e64c7-5561-7e54-acd2-5d3ae36d0e4c" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7646-b2d7-12f3a965a405" xlink:to="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019e64c7-5561-7e54-acd2-5d3ae36d0e4c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_019e64c7-5561-7f0e-a8e0-d894ae5d0158" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7646-b2d7-12f3a965a405" xlink:to="loc_srt_MultifamilyMember_019e64c7-5561-7f0e-a8e0-d894ae5d0158" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FarmlandLoansMember_019e64c7-5561-722f-918e-a2a37b507d5c" xlink:href="msbi-20260630.xsd#msbi_FarmlandLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7646-b2d7-12f3a965a405" xlink:to="loc_msbi_FarmlandLoansMember_019e64c7-5561-722f-918e-a2a37b507d5c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-7e9f-9784-2c54ef518f1e" xlink:href="msbi-20260630.xsd#msbi_ConstructionAndLandDevelopmentLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7646-b2d7-12f3a965a405" xlink:to="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019e64c7-5561-7e9f-9784-2c54ef518f1e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-7006-8a84-d78dcc4d3dfa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7646-b2d7-12f3a965a405" xlink:to="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-7006-8a84-d78dcc4d3dfa" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-7363-a356-3b078457a04a" xlink:href="msbi-20260630.xsd#msbi_OtherResidentialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7646-b2d7-12f3a965a405" xlink:to="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-7363-a356-3b078457a04a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerLoanMember_019e64c7-5561-7e15-aa3d-c7aacfb2da83" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7646-b2d7-12f3a965a405" xlink:to="loc_us-gaap_ConsumerLoanMember_019e64c7-5561-7e15-aa3d-c7aacfb2da83" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherConsumerLoansMember_019e64c7-5561-7039-b5bb-5959aace6c63" xlink:href="msbi-20260630.xsd#msbi_OtherConsumerLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7646-b2d7-12f3a965a405" xlink:to="loc_msbi_OtherConsumerLoansMember_019e64c7-5561-7039-b5bb-5959aace6c63" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7e42-bc0b-e6810e90bd04" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7731-97ec-c1fbb28e238e" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7e42-bc0b-e6810e90bd04" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7e42-bc0b-e6810e90bd04_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7e42-bc0b-e6810e90bd04" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7e42-bc0b-e6810e90bd04_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-73be-ac35-e426695adef8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7e42-bc0b-e6810e90bd04" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-73be-ac35-e426695adef8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-74f7-a481-9908ca99ce50" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-73be-ac35-e426695adef8" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-74f7-a481-9908ca99ce50" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-7669-90ee-ae52f9ec14db" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-73be-ac35-e426695adef8" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-7669-90ee-ae52f9ec14db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_019e64c7-5561-7662-b2ee-f4462bc585e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-73be-ac35-e426695adef8" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_019e64c7-5561-7662-b2ee-f4462bc585e9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasesPortfolioSegmentMember_019e64c7-5561-75ed-a60c-14ad9ff8e03d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeasesPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-73be-ac35-e426695adef8" xlink:to="loc_us-gaap_FinanceLeasesPortfolioSegmentMember_019e64c7-5561-75ed-a60c-14ad9ff8e03d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_LoanPortfoliosExcludingCommercialMember_019e64c7-5561-7b0a-9509-3f93c4415bed" xlink:href="msbi-20260630.xsd#msbi_LoanPortfoliosExcludingCommercialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-73be-ac35-e426695adef8" xlink:to="loc_msbi_LoanPortfoliosExcludingCommercialMember_019e64c7-5561-7b0a-9509-3f93c4415bed" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentAxis_019e64c7-5561-74d8-a7f8-93c4ee320b92" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InternalCreditAssessmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7731-97ec-c1fbb28e238e" xlink:to="loc_us-gaap_InternalCreditAssessmentAxis_019e64c7-5561-74d8-a7f8-93c4ee320b92" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-74d8-a7f8-93c4ee320b92_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_019e64c7-5561-74d8-a7f8-93c4ee320b92" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-74d8-a7f8-93c4ee320b92_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-70dc-841a-25568f7fb9ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_019e64c7-5561-74d8-a7f8-93c4ee320b92" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-70dc-841a-25568f7fb9ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PassMember_019e64c7-5561-7a1f-bfc0-c8b9c3de1b6a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PassMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-70dc-841a-25568f7fb9ca" xlink:to="loc_us-gaap_PassMember_019e64c7-5561-7a1f-bfc0-c8b9c3de1b6a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SpecialMentionMember_019e64c7-5561-7b9a-bddb-a93d9b27e3e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SpecialMentionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-70dc-841a-25568f7fb9ca" xlink:to="loc_us-gaap_SpecialMentionMember_019e64c7-5561-7b9a-bddb-a93d9b27e3e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubstandardMember_019e64c7-5561-7d06-8e6f-92f1f116256c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubstandardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-70dc-841a-25568f7fb9ca" xlink:to="loc_us-gaap_SubstandardMember_019e64c7-5561-7d06-8e6f-92f1f116256c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_SubstandardNonaccrualMember_019e64c7-5561-7170-b5b9-77a70a7bd4fc" xlink:href="msbi-20260630.xsd#msbi_SubstandardNonaccrualMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-70dc-841a-25568f7fb9ca" xlink:to="loc_msbi_SubstandardNonaccrualMember_019e64c7-5561-7170-b5b9-77a70a7bd4fc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DoubtfulMember_019e64c7-5561-730e-8195-e9a00040d8cd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DoubtfulMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-70dc-841a-25568f7fb9ca" xlink:to="loc_us-gaap_DoubtfulMember_019e64c7-5561-730e-8195-e9a00040d8cd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_NotGradedMember_019e64c7-5561-729a-baf2-3cb1b6584f99" xlink:href="msbi-20260630.xsd#msbi_NotGradedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e64c7-5561-70dc-841a-25568f7fb9ca" xlink:to="loc_msbi_NotGradedMember_019e64c7-5561-729a-baf2-3cb1b6584f99" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_019e64c7-5561-7e46-ad78-bd7ae6138743" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentPerformanceStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7731-97ec-c1fbb28e238e" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_019e64c7-5561-7e46-ad78-bd7ae6138743" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_019e64c7-5561-7e46-ad78-bd7ae6138743_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentPerformanceStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_019e64c7-5561-7e46-ad78-bd7ae6138743" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_019e64c7-5561-7e46-ad78-bd7ae6138743_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_019e64c7-5561-7d8d-b759-ee0cd5345a4f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentPerformanceStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_019e64c7-5561-7e46-ad78-bd7ae6138743" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_019e64c7-5561-7d8d-b759-ee0cd5345a4f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformingFinancingReceivableMember_019e64c7-5561-78e6-bf1b-d9c624d3ecc6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PerformingFinancingReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_019e64c7-5561-7d8d-b759-ee0cd5345a4f" xlink:to="loc_us-gaap_PerformingFinancingReceivableMember_019e64c7-5561-78e6-bf1b-d9c624d3ecc6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonperformingFinancingReceivableMember_019e64c7-5561-760c-b5ca-19583a861701" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonperformingFinancingReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_019e64c7-5561-7d8d-b759-ee0cd5345a4f" xlink:to="loc_us-gaap_NonperformingFinancingReceivableMember_019e64c7-5561-760c-b5ca-19583a861701" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear_019e64c7-5561-780f-b930-a756b8db2c5b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7836-8aa7-4bdc81f4d82a" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear_019e64c7-5561-780f-b930-a756b8db2c5b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear_019e64c7-5561-7742-b66c-d58aba1f2759" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7836-8aa7-4bdc81f4d82a" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear_019e64c7-5561-7742-b66c-d58aba1f2759" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear_019e64c7-5561-765e-a551-5e31eca39b3f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7836-8aa7-4bdc81f4d82a" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear_019e64c7-5561-765e-a551-5e31eca39b3f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear_019e64c7-5561-704d-9980-7afdff1baee9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7836-8aa7-4bdc81f4d82a" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear_019e64c7-5561-704d-9980-7afdff1baee9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear_019e64c7-5561-7365-8be2-5f16595dd79f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7836-8aa7-4bdc81f4d82a" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear_019e64c7-5561-7365-8be2-5f16595dd79f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear_019e64c7-5561-7436-b27f-93e04b9e5c21" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7836-8aa7-4bdc81f4d82a" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear_019e64c7-5561-7436-b27f-93e04b9e5c21" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolving_019e64c7-5561-7e7a-802a-ae0183dc3807" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestRevolving"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7836-8aa7-4bdc81f4d82a" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolving_019e64c7-5561-7e7a-802a-ae0183dc3807" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e64c7-5561-7ec1-85c8-28ee7237968b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7836-8aa7-4bdc81f4d82a" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e64c7-5561-7ec1-85c8-28ee7237968b" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/LOANSGrossWriteoffsDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#LOANSGrossWriteoffsDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/LOANSGrossWriteoffsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7d7c-9029-431ddce5ed8d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7415-af01-85ca483e372d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7d7c-9029-431ddce5ed8d" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7415-af01-85ca483e372d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7155-b2ae-3cb5bc58c6d5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7415-af01-85ca483e372d" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7155-b2ae-3cb5bc58c6d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7155-b2ae-3cb5bc58c6d5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7155-b2ae-3cb5bc58c6d5" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-7155-b2ae-3cb5bc58c6d5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-73e4-83c9-53e0c1c690b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5561-7155-b2ae-3cb5bc58c6d5" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-73e4-83c9-53e0c1c690b2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-77d2-86d0-c49f200bcf20" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-73e4-83c9-53e0c1c690b2" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_019e64c7-5561-77d2-86d0-c49f200bcf20" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-705d-8091-9821f0709175" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-73e4-83c9-53e0c1c690b2" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5561-705d-8091-9821f0709175" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_019e64c7-5561-7d90-8518-ab75e3aa5895" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-73e4-83c9-53e0c1c690b2" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_019e64c7-5561-7d90-8518-ab75e3aa5895" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasesPortfolioSegmentMember_019e64c7-5561-70f5-97ce-c87ef606e1f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeasesPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-73e4-83c9-53e0c1c690b2" xlink:to="loc_us-gaap_FinanceLeasesPortfolioSegmentMember_019e64c7-5561-70f5-97ce-c87ef606e1f8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_LoanPortfoliosExcludingCommercialMember_019e64c7-5561-717d-986b-fad1cf6da5fc" xlink:href="msbi-20260630.xsd#msbi_LoanPortfoliosExcludingCommercialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5561-73e4-83c9-53e0c1c690b2" xlink:to="loc_msbi_LoanPortfoliosExcludingCommercialMember_019e64c7-5561-717d-986b-fad1cf6da5fc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7d94-aa79-5a982e0abaf0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e64c7-5561-7415-af01-85ca483e372d" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7d94-aa79-5a982e0abaf0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7d94-aa79-5a982e0abaf0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7d94-aa79-5a982e0abaf0" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7d94-aa79-5a982e0abaf0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7cb9-8baf-95a1d21581f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e64c7-5561-7d94-aa79-5a982e0abaf0" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7cb9-8baf-95a1d21581f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialLoansExcludingOtherMember_019e64c7-5561-7736-8360-bc85cc03efe1" xlink:href="msbi-20260630.xsd#msbi_CommercialLoansExcludingOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7cb9-8baf-95a1d21581f1" xlink:to="loc_msbi_CommercialLoansExcludingOtherMember_019e64c7-5561-7736-8360-bc85cc03efe1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-7afa-80a6-b79846ac441e" xlink:href="msbi-20260630.xsd#msbi_CommercialOtherLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7cb9-8baf-95a1d21581f1" xlink:to="loc_msbi_CommercialOtherLoansMember_019e64c7-5561-7afa-80a6-b79846ac441e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019e64c7-5561-7f96-bf64-6a13eec20ea9" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateNonOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7cb9-8baf-95a1d21581f1" xlink:to="loc_msbi_CommercialRealEstateNonOwnerOccupiedLoansMember_019e64c7-5561-7f96-bf64-6a13eec20ea9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019e6dab-1c49-7039-b81d-602bfb262291" xlink:href="msbi-20260630.xsd#msbi_CommercialRealEstateOwnerOccupiedLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7cb9-8baf-95a1d21581f1" xlink:to="loc_msbi_CommercialRealEstateOwnerOccupiedLoansMember_019e6dab-1c49-7039-b81d-602bfb262291" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_019e64c7-5561-7a66-a48e-00f3c222d4f3" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7cb9-8baf-95a1d21581f1" xlink:to="loc_srt_MultifamilyMember_019e64c7-5561-7a66-a48e-00f3c222d4f3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019f65db-3def-728a-8744-3ec89ec92534" xlink:href="msbi-20260630.xsd#msbi_ConstructionAndLandDevelopmentLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7cb9-8baf-95a1d21581f1" xlink:to="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019f65db-3def-728a-8744-3ec89ec92534" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-7209-b68d-ef801d7f0a88" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7cb9-8baf-95a1d21581f1" xlink:to="loc_us-gaap_RealEstateLoanMember_019e64c7-5561-7209-b68d-ef801d7f0a88" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-7d2b-9fae-b579e3a544d1" xlink:href="msbi-20260630.xsd#msbi_OtherResidentialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7cb9-8baf-95a1d21581f1" xlink:to="loc_msbi_OtherResidentialLoansMember_019e64c7-5561-7d2b-9fae-b579e3a544d1" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ConsumerLoansExcludingOtherMember_019e64c7-5561-7a3f-a2c1-37a7ee3809de" xlink:href="msbi-20260630.xsd#msbi_ConsumerLoansExcludingOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7cb9-8baf-95a1d21581f1" xlink:to="loc_msbi_ConsumerLoansExcludingOtherMember_019e64c7-5561-7a3f-a2c1-37a7ee3809de" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherConsumerLoansMember_019e64c7-5561-7e5d-a1b9-e94edcdc7998" xlink:href="msbi-20260630.xsd#msbi_OtherConsumerLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e64c7-5561-7cb9-8baf-95a1d21581f1" xlink:to="loc_msbi_OtherConsumerLoansMember_019e64c7-5561-7e5d-a1b9-e94edcdc7998" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff_019e64c7-5561-7394-bc96-99a42a2e3a82" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7d7c-9029-431ddce5ed8d" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff_019e64c7-5561-7394-bc96-99a42a2e3a82" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff_019e64c7-5561-745f-bf48-243f9f2e5f76" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7d7c-9029-431ddce5ed8d" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff_019e64c7-5561-745f-bf48-243f9f2e5f76" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff_019e64c7-5561-767b-af15-2e2a7e110654" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7d7c-9029-431ddce5ed8d" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff_019e64c7-5561-767b-af15-2e2a7e110654" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff_019e64c7-5561-7783-8c63-7bbaaaa9ad73" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7d7c-9029-431ddce5ed8d" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff_019e64c7-5561-7783-8c63-7bbaaaa9ad73" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff_019e64c7-5561-7cfa-8790-b0ad9f6bc4ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7d7c-9029-431ddce5ed8d" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff_019e64c7-5561-7cfa-8790-b0ad9f6bc4ca" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff_019e64c7-5561-74a8-b590-aed581551579" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7d7c-9029-431ddce5ed8d" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff_019e64c7-5561-74a8-b590-aed581551579" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FinancingReceivableExcludingAccruedInterestOriginatedRevolvingWriteoff_019e64c7-5561-76b3-beb6-1f47d9b2a74e" xlink:href="msbi-20260630.xsd#msbi_FinancingReceivableExcludingAccruedInterestOriginatedRevolvingWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7d7c-9029-431ddce5ed8d" xlink:to="loc_msbi_FinancingReceivableExcludingAccruedInterestOriginatedRevolvingWriteoff_019e64c7-5561-76b3-beb6-1f47d9b2a74e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_019e64c7-5561-7855-a88f-f5ef167e73ff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e64c7-5561-7d7c-9029-431ddce5ed8d" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_019e64c7-5561-7855-a88f-f5ef167e73ff" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/PREMISESEQUIPMENTANDLEASESPremisesandEquipmentDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#PREMISESEQUIPMENTANDLEASESPremisesandEquipmentDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/PREMISESEQUIPMENTANDLEASESPremisesandEquipmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-7e59-b689-9aa05113c445" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e64c7-5561-7f43-8653-ef832847205c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-7e59-b689-9aa05113c445" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e64c7-5561-7f43-8653-ef832847205c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e64c7-5561-745c-b6fc-f7a9b025263d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e64c7-5561-7f43-8653-ef832847205c" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e64c7-5561-745c-b6fc-f7a9b025263d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e64c7-5561-745c-b6fc-f7a9b025263d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e64c7-5561-745c-b6fc-f7a9b025263d" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e64c7-5561-745c-b6fc-f7a9b025263d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e64c7-5561-75a0-8ade-5e25c56cdaeb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e64c7-5561-745c-b6fc-f7a9b025263d" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e64c7-5561-75a0-8ade-5e25c56cdaeb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_019e64c7-5561-7f19-8b84-e4cb9d5b6ebc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LandMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e64c7-5561-75a0-8ade-5e25c56cdaeb" xlink:to="loc_us-gaap_LandMember_019e64c7-5561-7f19-8b84-e4cb9d5b6ebc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_019e64c7-5561-7a0f-9534-3f9e32a5b78f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e64c7-5561-75a0-8ade-5e25c56cdaeb" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_019e64c7-5561-7a0f-9534-3f9e32a5b78f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquipmentMember_019e64c7-5561-73e5-870b-143a49759a0f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e64c7-5561-75a0-8ade-5e25c56cdaeb" xlink:to="loc_us-gaap_EquipmentMember_019e64c7-5561-73e5-870b-143a49759a0f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentExcludingLessorAssetUnderOperatingLeaseBeforeAccumulatedDepreciation_019e64c7-5561-7a19-bdb0-e79d707bedf1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentExcludingLessorAssetUnderOperatingLeaseBeforeAccumulatedDepreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-7e59-b689-9aa05113c445" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentExcludingLessorAssetUnderOperatingLeaseBeforeAccumulatedDepreciation_019e64c7-5561-7a19-bdb0-e79d707bedf1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseGross_019e64c7-5561-7567-bd64-c0a866563028" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-7e59-b689-9aa05113c445" xlink:to="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseGross_019e64c7-5561-7567-bd64-c0a866563028" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_019e64c7-5561-79c3-bf03-9eb9d0a9e663" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-7e59-b689-9aa05113c445" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_019e64c7-5561-79c3-bf03-9eb9d0a9e663" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_019e64c7-5561-72ce-8f1d-4a6117333222" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-7e59-b689-9aa05113c445" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_019e64c7-5561-72ce-8f1d-4a6117333222" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019e64c7-5561-7e95-84a6-df336a6830e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-7e59-b689-9aa05113c445" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_019e64c7-5561-7e95-84a6-df336a6830e4" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/PREMISESEQUIPMENTANDLEASESNarrativeDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#PREMISESEQUIPMENTANDLEASESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/PREMISESEQUIPMENTANDLEASESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-744c-8d48-cbee374992a7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e64c7-5561-79e0-9fba-dd7325e5021a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-744c-8d48-cbee374992a7" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e64c7-5561-79e0-9fba-dd7325e5021a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e64c7-5561-704c-a6c7-f642019da361" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e64c7-5561-79e0-9fba-dd7325e5021a" xlink:to="loc_srt_RangeAxis_019e64c7-5561-704c-a6c7-f642019da361" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e64c7-5561-704c-a6c7-f642019da361_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e64c7-5561-704c-a6c7-f642019da361" xlink:to="loc_srt_RangeMember_019e64c7-5561-704c-a6c7-f642019da361_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e64c7-5561-7be5-af20-537ebf3ad3f7" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e64c7-5561-704c-a6c7-f642019da361" xlink:to="loc_srt_RangeMember_019e64c7-5561-7be5-af20-537ebf3ad3f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019e64c7-5561-7a9a-b87a-999fe7aa2f57" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e64c7-5561-7be5-af20-537ebf3ad3f7" xlink:to="loc_srt_MinimumMember_019e64c7-5561-7a9a-b87a-999fe7aa2f57" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e64c7-5561-7c63-885c-d990a4782ffa" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e64c7-5561-7be5-af20-537ebf3ad3f7" xlink:to="loc_srt_MaximumMember_019e64c7-5561-7c63-885c-d990a4782ffa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_019e64c7-5561-7f7e-9c9c-b06b1d555c30" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-744c-8d48-cbee374992a7" xlink:to="loc_us-gaap_Depreciation_019e64c7-5561-7f7e-9c9c-b06b1d555c30" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseTermOfContract_019e64c7-5561-702b-baed-43b0a65ae885" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-744c-8d48-cbee374992a7" xlink:to="loc_us-gaap_LesseeOperatingLeaseTermOfContract_019e64c7-5561-702b-baed-43b0a65ae885" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_019e64c7-5561-78ba-9379-e4973d307281" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseRenewalTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-744c-8d48-cbee374992a7" xlink:to="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_019e64c7-5561-78ba-9379-e4973d307281" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_019e64c7-5561-7ccb-8ce3-2ec1937eaa81" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-744c-8d48-cbee374992a7" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_019e64c7-5561-7ccb-8ce3-2ec1937eaa81" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_019e64c7-5561-7d32-8a63-1747a47827f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-744c-8d48-cbee374992a7" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_019e64c7-5561-7d32-8a63-1747a47827f5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_019e64c7-5561-7ba8-884b-a1e5c0811972" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-744c-8d48-cbee374992a7" xlink:to="loc_us-gaap_OperatingLeaseLiability_019e64c7-5561-7ba8-884b-a1e5c0811972" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList_019e64c7-5561-73e1-b43b-9741721b0eec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e64c7-5561-744c-8d48-cbee374992a7" xlink:to="loc_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList_019e64c7-5561-73e1-b43b-9741721b0eec" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsinStatementofFinancialPositionDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsinStatementofFinancialPositionDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsinStatementofFinancialPositionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_019e64c7-5561-7034-a0c5-081f271b2be8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019e64c7-5561-7868-b9a1-f37e8dbf9595" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_019e64c7-5561-7034-a0c5-081f271b2be8" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019e64c7-5561-7868-b9a1-f37e8dbf9595" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7d5b-bd66-e26b1e370aa0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019e64c7-5561-7868-b9a1-f37e8dbf9595" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7d5b-bd66-e26b1e370aa0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7d5b-bd66-e26b1e370aa0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7d5b-bd66-e26b1e370aa0" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7d5b-bd66-e26b1e370aa0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-78c1-8bc3-6f686051f80e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7d5b-bd66-e26b1e370aa0" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-78c1-8bc3-6f686051f80e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_InvestmentSecuritiesAvailableForSaleMember_019e64c7-5561-7c22-926a-5bc969818bd6" xlink:href="msbi-20260630.xsd#msbi_InvestmentSecuritiesAvailableForSaleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-78c1-8bc3-6f686051f80e" xlink:to="loc_msbi_InvestmentSecuritiesAvailableForSaleMember_019e64c7-5561-7c22-926a-5bc969818bd6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019e64c7-5561-77a6-8fe2-233aac80bef8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-78c1-8bc3-6f686051f80e" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019e64c7-5561-77a6-8fe2-233aac80bef8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FHLBAdvancesBrokeredCDsAndOtherBorrowingsMember_019e64c7-5561-7985-a400-f331ff5020a0" xlink:href="msbi-20260630.xsd#msbi_FHLBAdvancesBrokeredCDsAndOtherBorrowingsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-78c1-8bc3-6f686051f80e" xlink:to="loc_msbi_FHLBAdvancesBrokeredCDsAndOtherBorrowingsMember_019e64c7-5561-7985-a400-f331ff5020a0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_019e64c7-5561-78bc-94db-139433031395" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-78c1-8bc3-6f686051f80e" xlink:to="loc_us-gaap_InterestRateSwapMember_019e64c7-5561-78bc-94db-139433031395" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateLockCommitmentsMember_019e64c7-5561-7226-bd72-505c8f77f957" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateLockCommitmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-78c1-8bc3-6f686051f80e" xlink:to="loc_us-gaap_InterestRateLockCommitmentsMember_019e64c7-5561-7226-bd72-505c8f77f957" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForwardContractsMember_019e64c7-5561-79e1-a984-189228476d90" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForwardContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-78c1-8bc3-6f686051f80e" xlink:to="loc_us-gaap_ForwardContractsMember_019e64c7-5561-79e1-a984-189228476d90" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7677-b3ba-742dfca79e50" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019e64c7-5561-7868-b9a1-f37e8dbf9595" xlink:to="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7677-b3ba-742dfca79e50" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-7677-b3ba-742dfca79e50_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7677-b3ba-742dfca79e50" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-7677-b3ba-742dfca79e50_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-7550-9573-a331d781e759" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7677-b3ba-742dfca79e50" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-7550-9573-a331d781e759" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_019e64c7-5561-7e09-adba-55934710d481" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-7550-9573-a331d781e759" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_019e64c7-5561-7e09-adba-55934710d481" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_019e64c7-5561-7455-98ff-c5cc54a11947" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-7550-9573-a331d781e759" xlink:to="loc_us-gaap_NondesignatedMember_019e64c7-5561-7455-98ff-c5cc54a11947" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_019e64c7-5561-70a9-b43d-31b2e8284147" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_019e64c7-5561-7034-a0c5-081f271b2be8" xlink:to="loc_us-gaap_DerivativeAssets_019e64c7-5561-70a9-b43d-31b2e8284147" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_019e64c7-5561-791c-8859-93b3958063cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_019e64c7-5561-7034-a0c5-081f271b2be8" xlink:to="loc_us-gaap_DerivativeLiabilities_019e64c7-5561-791c-8859-93b3958063cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_019e64c7-5561-7423-a67d-4895d71eead7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_019e64c7-5561-7034-a0c5-081f271b2be8" xlink:to="loc_us-gaap_DerivativeNotionalAmount_019e64c7-5561-7423-a67d-4895d71eead7" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/DERIVATIVEINSTRUMENTSScheduleofFairValueHedgingInstrumentsStatementsofFinancialPerformanceandFinancialPositionLocationDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#DERIVATIVEINSTRUMENTSScheduleofFairValueHedgingInstrumentsStatementsofFinancialPerformanceandFinancialPositionLocationDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/DERIVATIVEINSTRUMENTSScheduleofFairValueHedgingInstrumentsStatementsofFinancialPerformanceandFinancialPositionLocationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7429-b45e-52753265b4c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7425-ac20-f54528c82fec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7429-b45e-52753265b4c1" xlink:to="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7425-ac20-f54528c82fec" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_019e64c7-5561-7c5a-b4e1-a234bcd1f386" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7425-ac20-f54528c82fec" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_019e64c7-5561-7c5a-b4e1-a234bcd1f386" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019e64c7-5561-7c5a-b4e1-a234bcd1f386_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019e64c7-5561-7c5a-b4e1-a234bcd1f386" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019e64c7-5561-7c5a-b4e1-a234bcd1f386_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019e64c7-5561-73af-87b5-5bf71f802646" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019e64c7-5561-7c5a-b4e1-a234bcd1f386" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019e64c7-5561-73af-87b5-5bf71f802646" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesMember_019e64c7-5561-7495-9f67-1f1cbbf11aaa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019e64c7-5561-73af-87b5-5bf71f802646" xlink:to="loc_us-gaap_DebtSecuritiesMember_019e64c7-5561-7495-9f67-1f1cbbf11aaa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgedAssetFairValueHedge_019e64c7-5561-7776-ae58-5be37ebf2514" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgedAssetFairValueHedge"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7429-b45e-52753265b4c1" xlink:to="loc_us-gaap_HedgedAssetFairValueHedge_019e64c7-5561-7776-ae58-5be37ebf2514" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgedAssetFairValueHedgeCumulativeIncreaseDecrease_019e64c7-5561-7aa6-8ec1-20f8e1c05469" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgedAssetFairValueHedgeCumulativeIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7429-b45e-52753265b4c1" xlink:to="loc_us-gaap_HedgedAssetFairValueHedgeCumulativeIncreaseDecrease_019e64c7-5561-7aa6-8ec1-20f8e1c05469" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsInFairValueHedgingRelationshipsonConsolidatedStatementsOfIncomeDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsInFairValueHedgingRelationshipsonConsolidatedStatementsOfIncomeDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsInFairValueHedgingRelationshipsonConsolidatedStatementsOfIncomeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7355-8039-626427cf5b46" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7d1e-9004-82979a8a1494" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7355-8039-626427cf5b46" xlink:to="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7d1e-9004-82979a8a1494" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-72dc-af98-1041afad92d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7d1e-9004-82979a8a1494" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-72dc-af98-1041afad92d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-72dc-af98-1041afad92d8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-72dc-af98-1041afad92d8" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-72dc-af98-1041afad92d8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7d2e-a5f2-228adb3319a7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-72dc-af98-1041afad92d8" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7d2e-a5f2-228adb3319a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_019e64c7-5561-799e-8eeb-0da5352e7bf7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7d2e-a5f2-228adb3319a7" xlink:to="loc_us-gaap_InterestRateContractMember_019e64c7-5561-799e-8eeb-0da5352e7bf7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019e64c7-5561-76ee-a95f-e21548e65bfe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7d1e-9004-82979a8a1494" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019e64c7-5561-76ee-a95f-e21548e65bfe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_019e64c7-5561-76ee-a95f-e21548e65bfe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019e64c7-5561-76ee-a95f-e21548e65bfe" xlink:to="loc_us-gaap_HedgingRelationshipDomain_019e64c7-5561-76ee-a95f-e21548e65bfe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_019e64c7-5561-79b5-b9bb-346bd404f1c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019e64c7-5561-76ee-a95f-e21548e65bfe" xlink:to="loc_us-gaap_HedgingRelationshipDomain_019e64c7-5561-79b5-b9bb-346bd404f1c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueHedgingMember_019e64c7-5561-782c-b776-6a4262df80a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_019e64c7-5561-79b5-b9bb-346bd404f1c9" xlink:to="loc_us-gaap_FairValueHedgingMember_019e64c7-5561-782c-b776-6a4262df80a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7a6d-adc3-5c0167ba8de3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7d1e-9004-82979a8a1494" xlink:to="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7a6d-adc3-5c0167ba8de3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-7a6d-adc3-5c0167ba8de3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7a6d-adc3-5c0167ba8de3" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-7a6d-adc3-5c0167ba8de3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-725b-ba7f-a83f136ecd1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7a6d-adc3-5c0167ba8de3" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-725b-ba7f-a83f136ecd1b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_019e64c7-5561-7fea-a292-675d34de9448" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-725b-ba7f-a83f136ecd1b" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_019e64c7-5561-7fea-a292-675d34de9448" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_019e64c7-5561-75c1-8adf-f09d34ec7768" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7355-8039-626427cf5b46" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_019e64c7-5561-75c1-8adf-f09d34ec7768" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInUnrealizedGainLossOnFairValueHedgingInstruments1_019e64c7-5561-7086-9d2b-1e691ad66e49" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ChangeInUnrealizedGainLossOnFairValueHedgingInstruments1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7355-8039-626427cf5b46" xlink:to="loc_us-gaap_ChangeInUnrealizedGainLossOnFairValueHedgingInstruments1_019e64c7-5561-7086-9d2b-1e691ad66e49" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7003-be26-fd6358432d85" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7556-b834-a165ff2ca22d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7003-be26-fd6358432d85" xlink:to="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7556-b834-a165ff2ca22d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7709-b61b-776b02e918d1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7556-b834-a165ff2ca22d" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7709-b61b-776b02e918d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7709-b61b-776b02e918d1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7709-b61b-776b02e918d1" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7709-b61b-776b02e918d1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7a0e-9734-632882b26579" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7709-b61b-776b02e918d1" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7a0e-9734-632882b26579" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_019e64c7-5561-72fe-a71e-f7b7434345c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7a0e-9734-632882b26579" xlink:to="loc_us-gaap_InterestRateContractMember_019e64c7-5561-72fe-a71e-f7b7434345c5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e64c7-5561-787f-8622-62af363f4f95" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfIncomeLocationBalanceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7556-b834-a165ff2ca22d" xlink:to="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e64c7-5561-787f-8622-62af363f4f95" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_019e64c7-5561-7d82-a8d6-e76d9d6120b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7003-be26-fd6358432d85" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_019e64c7-5561-7d82-a8d6-e76d9d6120b8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_019e64c7-5561-7fad-9216-544b92ce6746" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7003-be26-fd6358432d85" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_019e64c7-5561-7fad-9216-544b92ce6746" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsDetails_1" xlink:type="simple" xlink:href="msbi-20260630.xsd#DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsDetails_1"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7003-be26-fd6358432d85" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7556-b834-a165ff2ca22d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7003-be26-fd6358432d85" xlink:to="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7556-b834-a165ff2ca22d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7709-b61b-776b02e918d1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019e64c7-5561-7556-b834-a165ff2ca22d" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7709-b61b-776b02e918d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7709-b61b-776b02e918d1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7709-b61b-776b02e918d1" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7709-b61b-776b02e918d1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7a0e-9734-632882b26579" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7709-b61b-776b02e918d1" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7a0e-9734-632882b26579" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_019e64c7-5561-72fe-a71e-f7b7434345c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7a0e-9734-632882b26579" xlink:to="loc_us-gaap_InterestRateContractMember_019e64c7-5561-72fe-a71e-f7b7434345c5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_019e64c7-5561-7d82-a8d6-e76d9d6120b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7003-be26-fd6358432d85" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_019e64c7-5561-7d82-a8d6-e76d9d6120b8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_019e64c7-5561-7fad-9216-544b92ce6746" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019e64c7-5561-7003-be26-fd6358432d85" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_019e64c7-5561-7fad-9216-544b92ce6746" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsNotDesignatedasAccountingHedgeDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsNotDesignatedasAccountingHedgeDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsNotDesignatedasAccountingHedgeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_019e64c7-5561-74b6-977e-d460cf001c22" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_019e64c7-5561-7163-9c60-5bf98e35ce1a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_019e64c7-5561-74b6-977e-d460cf001c22" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_019e64c7-5561-7163-9c60-5bf98e35ce1a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7064-9846-769141b5aeda" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_019e64c7-5561-7163-9c60-5bf98e35ce1a" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7064-9846-769141b5aeda" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7064-9846-769141b5aeda_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7064-9846-769141b5aeda" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7064-9846-769141b5aeda_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7648-af9f-c0839552d57c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7064-9846-769141b5aeda" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7648-af9f-c0839552d57c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_019e64c7-5561-73e8-9e13-3dd1121f9176" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7648-af9f-c0839552d57c" xlink:to="loc_us-gaap_InterestRateContractMember_019e64c7-5561-73e8-9e13-3dd1121f9176" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7d26-b026-9a80e3734718" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_019e64c7-5561-7163-9c60-5bf98e35ce1a" xlink:to="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7d26-b026-9a80e3734718" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-7d26-b026-9a80e3734718_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7d26-b026-9a80e3734718" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-7d26-b026-9a80e3734718_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-797c-ac4b-3b04e3fce89b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7d26-b026-9a80e3734718" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-797c-ac4b-3b04e3fce89b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_019e64c7-5561-7d60-9354-089456fe856d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-797c-ac4b-3b04e3fce89b" xlink:to="loc_us-gaap_NondesignatedMember_019e64c7-5561-7d60-9354-089456fe856d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e64c7-5561-7755-a728-d8a6a62ce7fa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfIncomeLocationBalanceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_019e64c7-5561-7163-9c60-5bf98e35ce1a" xlink:to="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e64c7-5561-7755-a728-d8a6a62ce7fa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_019e64c7-5561-7f3b-88fc-909db14c94d9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnDerivativeInstrumentsNetPretax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_019e64c7-5561-74b6-977e-d460cf001c22" xlink:to="loc_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_019e64c7-5561-7f3b-88fc-909db14c94d9" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsNotDesignatedasAccountingHedgeDetails_1" xlink:type="simple" xlink:href="msbi-20260630.xsd#DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsNotDesignatedasAccountingHedgeDetails_1"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsNotDesignatedasAccountingHedgeDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_019e64c7-5561-74b6-977e-d460cf001c22" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_019e64c7-5561-7163-9c60-5bf98e35ce1a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_019e64c7-5561-74b6-977e-d460cf001c22" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_019e64c7-5561-7163-9c60-5bf98e35ce1a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7064-9846-769141b5aeda" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_019e64c7-5561-7163-9c60-5bf98e35ce1a" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7064-9846-769141b5aeda" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7064-9846-769141b5aeda_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7064-9846-769141b5aeda" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7064-9846-769141b5aeda_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7648-af9f-c0839552d57c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e64c7-5561-7064-9846-769141b5aeda" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7648-af9f-c0839552d57c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_019e64c7-5561-73e8-9e13-3dd1121f9176" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e64c7-5561-7648-af9f-c0839552d57c" xlink:to="loc_us-gaap_InterestRateContractMember_019e64c7-5561-73e8-9e13-3dd1121f9176" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7d26-b026-9a80e3734718" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_019e64c7-5561-7163-9c60-5bf98e35ce1a" xlink:to="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7d26-b026-9a80e3734718" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-7d26-b026-9a80e3734718_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7d26-b026-9a80e3734718" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-7d26-b026-9a80e3734718_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-797c-ac4b-3b04e3fce89b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e64c7-5561-7d26-b026-9a80e3734718" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-797c-ac4b-3b04e3fce89b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_019e64c7-5561-7d60-9354-089456fe856d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019e64c7-5561-797c-ac4b-3b04e3fce89b" xlink:to="loc_us-gaap_NondesignatedMember_019e64c7-5561-7d60-9354-089456fe856d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_019e64c7-5561-7f3b-88fc-909db14c94d9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnDerivativeInstrumentsNetPretax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_019e64c7-5561-74b6-977e-d460cf001c22" xlink:to="loc_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_019e64c7-5561-7f3b-88fc-909db14c94d9" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/SHORTTERMBORROWINGSScheduleofShortTermBorrowingsDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#SHORTTERMBORROWINGSScheduleofShortTermBorrowingsDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/SHORTTERMBORROWINGSScheduleofShortTermBorrowingsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtLineItems_019e64c7-5561-750e-9ded-0ce875422ab3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShortTermDebtTable_019e64c7-5561-78a6-aa83-e3c5ec4edfd6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShortTermDebtTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortTermDebtLineItems_019e64c7-5561-750e-9ded-0ce875422ab3" xlink:to="loc_us-gaap_ScheduleOfShortTermDebtTable_019e64c7-5561-78a6-aa83-e3c5ec4edfd6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_019e64c7-5561-7c66-9aea-03be5764a4b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_019e64c7-5561-78a6-aa83-e3c5ec4edfd6" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_019e64c7-5561-7c66-9aea-03be5764a4b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019e64c7-5561-7c66-9aea-03be5764a4b1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019e64c7-5561-7c66-9aea-03be5764a4b1" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019e64c7-5561-7c66-9aea-03be5764a4b1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019e64c7-5561-747d-9582-2fd380b5275a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019e64c7-5561-7c66-9aea-03be5764a4b1" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019e64c7-5561-747d-9582-2fd380b5275a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_RepurchaseAgreementMember_019e64c7-5561-7347-a5d5-0fe725f03e2e" xlink:href="msbi-20260630.xsd#msbi_RepurchaseAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_019e64c7-5561-747d-9582-2fd380b5275a" xlink:to="loc_msbi_RepurchaseAgreementMember_019e64c7-5561-7347-a5d5-0fe725f03e2e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_019e64c7-5561-726f-a1cf-47f9f641dab2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_019e64c7-5561-750e-9ded-0ce875422ab3" xlink:to="loc_us-gaap_ShortTermBorrowings_019e64c7-5561-726f-a1cf-47f9f641dab2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShorttermDebtAverageOutstandingAmount_019e64c7-5561-7344-a177-0adea44603c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShorttermDebtAverageOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_019e64c7-5561-750e-9ded-0ce875422ab3" xlink:to="loc_us-gaap_ShorttermDebtAverageOutstandingAmount_019e64c7-5561-7344-a177-0adea44603c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShorttermDebtMaximumMonthendOutstandingAmount_019e64c7-5561-70eb-ba86-71708db8fff3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShorttermDebtMaximumMonthendOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_019e64c7-5561-750e-9ded-0ce875422ab3" xlink:to="loc_us-gaap_ShorttermDebtMaximumMonthendOutstandingAmount_019e64c7-5561-70eb-ba86-71708db8fff3" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/SHORTTERMBORROWINGSNarrativeDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#SHORTTERMBORROWINGSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/SHORTTERMBORROWINGSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtLineItems_019e64c7-5561-76e3-88b8-1e5739f3e0bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShortTermDebtTable_019e64c7-5561-7a7e-96cf-18f6874996fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShortTermDebtTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortTermDebtLineItems_019e64c7-5561-76e3-88b8-1e5739f3e0bc" xlink:to="loc_us-gaap_ScheduleOfShortTermDebtTable_019e64c7-5561-7a7e-96cf-18f6874996fd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e64c7-5561-7653-8f03-0240ca152dd0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_019e64c7-5561-7a7e-96cf-18f6874996fd" xlink:to="loc_srt_RangeAxis_019e64c7-5561-7653-8f03-0240ca152dd0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e64c7-5561-7653-8f03-0240ca152dd0_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e64c7-5561-7653-8f03-0240ca152dd0" xlink:to="loc_srt_RangeMember_019e64c7-5561-7653-8f03-0240ca152dd0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e64c7-5561-73a0-a269-8b16699c5e59" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e64c7-5561-7653-8f03-0240ca152dd0" xlink:to="loc_srt_RangeMember_019e64c7-5561-73a0-a269-8b16699c5e59" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019e64c7-5561-7f92-8846-f162e55dbe67" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e64c7-5561-73a0-a269-8b16699c5e59" xlink:to="loc_srt_MinimumMember_019e64c7-5561-7f92-8846-f162e55dbe67" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e64c7-5561-743c-a429-3d9fe426f914" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e64c7-5561-73a0-a269-8b16699c5e59" xlink:to="loc_srt_MaximumMember_019e64c7-5561-743c-a429-3d9fe426f914" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_019e64c7-5561-7995-b538-42cf9d50777d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_019e64c7-5561-7a7e-96cf-18f6874996fd" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_019e64c7-5561-7995-b538-42cf9d50777d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019e64c7-5561-7995-b538-42cf9d50777d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019e64c7-5561-7995-b538-42cf9d50777d" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019e64c7-5561-7995-b538-42cf9d50777d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019e64c7-5561-7a53-8fe9-b73974d17dd5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019e64c7-5561-7995-b538-42cf9d50777d" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019e64c7-5561-7a53-8fe9-b73974d17dd5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_RepurchaseAgreementMember_019e64c7-5561-7bfb-aa0b-8fae6522a3b8" xlink:href="msbi-20260630.xsd#msbi_RepurchaseAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_019e64c7-5561-7a53-8fe9-b73974d17dd5" xlink:to="loc_msbi_RepurchaseAgreementMember_019e64c7-5561-7bfb-aa0b-8fae6522a3b8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SecuritiesSoldUnderAgreementsToRepurchaseAverageRatePaid_019e64c7-5561-7612-9a16-a35b8942d939" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SecuritiesSoldUnderAgreementsToRepurchaseAverageRatePaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_019e64c7-5561-76e3-88b8-1e5739f3e0bc" xlink:to="loc_srt_SecuritiesSoldUnderAgreementsToRepurchaseAverageRatePaid_019e64c7-5561-7612-9a16-a35b8942d939" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralizedAgreements_019e64c7-5561-72db-a7e8-282792492c0f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralizedAgreements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_019e64c7-5561-76e3-88b8-1e5739f3e0bc" xlink:to="loc_us-gaap_CollateralizedAgreements_019e64c7-5561-72db-a7e8-282792492c0f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtWeightedAverageInterestRateOverTime_019e64c7-5561-7506-a578-615afe50f34f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtWeightedAverageInterestRateOverTime"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_019e64c7-5561-76e3-88b8-1e5739f3e0bc" xlink:to="loc_us-gaap_ShortTermDebtWeightedAverageInterestRateOverTime_019e64c7-5561-7506-a578-615afe50f34f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/FHLBADVANCESSummaryofFHLBAdvancesDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#FHLBADVANCESSummaryofFHLBAdvancesDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/FHLBADVANCESSummaryofFHLBAdvancesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems_019e64c7-5561-7438-83dc-ce6e3ce2dd4c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019e64c7-5561-796c-ba03-5fd486f09b3f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems_019e64c7-5561-7438-83dc-ce6e3ce2dd4c" xlink:to="loc_us-gaap_DebtInstrumentTable_019e64c7-5561-796c-ba03-5fd486f09b3f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_019e64c7-5561-7cf4-b047-c5e3a87a2ab5" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e64c7-5561-796c-ba03-5fd486f09b3f" xlink:to="loc_srt_ConsolidatedEntitiesAxis_019e64c7-5561-7cf4-b047-c5e3a87a2ab5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_019e64c7-5561-7cf4-b047-c5e3a87a2ab5_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_019e64c7-5561-7cf4-b047-c5e3a87a2ab5" xlink:to="loc_srt_ConsolidatedEntitiesDomain_019e64c7-5561-7cf4-b047-c5e3a87a2ab5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_019e64c7-5561-7694-abec-adf06e20f61e" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_019e64c7-5561-7cf4-b047-c5e3a87a2ab5" xlink:to="loc_srt_ConsolidatedEntitiesDomain_019e64c7-5561-7694-abec-adf06e20f61e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_MidlandStatesBankMember_019e64c7-5561-7205-80ce-ef1bf1fe5a0b" xlink:href="msbi-20260630.xsd#msbi_MidlandStatesBankMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_019e64c7-5561-7694-abec-adf06e20f61e" xlink:to="loc_msbi_MidlandStatesBankMember_019e64c7-5561-7205-80ce-ef1bf1fe5a0b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e64c7-5561-79cb-b8ec-36f22b64ff9b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e64c7-5561-796c-ba03-5fd486f09b3f" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e64c7-5561-79cb-b8ec-36f22b64ff9b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e64c7-5561-79cb-b8ec-36f22b64ff9b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e64c7-5561-79cb-b8ec-36f22b64ff9b" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e64c7-5561-79cb-b8ec-36f22b64ff9b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e64c7-5561-75c2-96c5-d3754d559bd4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e64c7-5561-79cb-b8ec-36f22b64ff9b" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e64c7-5561-75c2-96c5-d3754d559bd4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FixedRateFixedTermLoanMaturingOctober2029Member_019e64c7-5561-7c03-801f-3ee66d6f864b" xlink:href="msbi-20260630.xsd#msbi_FixedRateFixedTermLoanMaturingOctober2029Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e64c7-5561-75c2-96c5-d3754d559bd4" xlink:to="loc_msbi_FixedRateFixedTermLoanMaturingOctober2029Member_019e64c7-5561-7c03-801f-3ee66d6f864b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_PutableFixedRateMaturingThroughMay2036Member_019e64c7-5561-7311-9fc2-31f4211b45f5" xlink:href="msbi-20260630.xsd#msbi_PutableFixedRateMaturingThroughMay2036Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e64c7-5561-75c2-96c5-d3754d559bd4" xlink:to="loc_msbi_PutableFixedRateMaturingThroughMay2036Member_019e64c7-5561-7311-9fc2-31f4211b45f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdvancesFromFederalHomeLoanBanks_019e64c7-5561-71f2-9287-e75452bb32fc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdvancesFromFederalHomeLoanBanks"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems_019e64c7-5561-7438-83dc-ce6e3ce2dd4c" xlink:to="loc_us-gaap_AdvancesFromFederalHomeLoanBanks_019e64c7-5561-71f2-9287-e75452bb32fc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresInterestRateAtPeriodEnd_019e64c7-5561-78aa-89d7-1007864df783" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresInterestRateAtPeriodEnd"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems_019e64c7-5561-7438-83dc-ce6e3ce2dd4c" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresInterestRateAtPeriodEnd_019e64c7-5561-78aa-89d7-1007864df783" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1_019e64c7-5561-7e5a-bc90-3840ceab03ae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems_019e64c7-5561-7438-83dc-ce6e3ce2dd4c" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1_019e64c7-5561-7e5a-bc90-3840ceab03ae" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds_019e64c7-5561-7ff0-b67c-2294ffbf8d33" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems_019e64c7-5561-7438-83dc-ce6e3ce2dd4c" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds_019e64c7-5561-7ff0-b67c-2294ffbf8d33" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/ACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSSScheduleofAccumulatedOtherComprehensiveIncomeLossDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#ACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSSScheduleofAccumulatedOtherComprehensiveIncomeLossDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/ACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSSScheduleofAccumulatedOtherComprehensiveIncomeLossDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e64c7-5561-737a-842c-30fa19e220f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019e64c7-5561-7544-868b-ba412f72fbd9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e64c7-5561-737a-842c-30fa19e220f1" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019e64c7-5561-7544-868b-ba412f72fbd9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e64c7-5561-71dd-84fa-9a6aac9f4d05" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019e64c7-5561-7544-868b-ba412f72fbd9" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e64c7-5561-71dd-84fa-9a6aac9f4d05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64c7-5561-71dd-84fa-9a6aac9f4d05_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64c7-5561-71dd-84fa-9a6aac9f4d05" xlink:to="loc_us-gaap_EquityComponentDomain_019e64c7-5561-71dd-84fa-9a6aac9f4d05_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64c7-5561-78cd-b729-3628a4f3d288" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64c7-5561-71dd-84fa-9a6aac9f4d05" xlink:to="loc_us-gaap_EquityComponentDomain_019e64c7-5561-78cd-b729-3628a4f3d288" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e64c7-5561-768d-bc57-a2519cee661d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64c7-5561-78cd-b729-3628a4f3d288" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e64c7-5561-768d-bc57-a2519cee661d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_019e64c7-5561-72ce-b2d4-0ca61600218f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e64c7-5561-768d-bc57-a2519cee661d" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_019e64c7-5561-72ce-b2d4-0ca61600218f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_019e64c7-5561-79b7-801d-bd95bff64e4b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e64c7-5561-768d-bc57-a2519cee661d" xlink:to="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_019e64c7-5561-79b7-801d-bd95bff64e4b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e64c7-5561-7e07-8c9a-5dfcdcb36aaf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e64c7-5561-737a-842c-30fa19e220f1" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e64c7-5561-7e07-8c9a-5dfcdcb36aaf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e64c7-5561-73aa-a1b3-7c0b03b982c6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e64c7-5561-7e07-8c9a-5dfcdcb36aaf" xlink:to="loc_us-gaap_StockholdersEquity_019e64c7-5561-73aa-a1b3-7c0b03b982c6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_019e64c7-5561-788f-83c9-3d99db9ac0bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e64c7-5561-7e07-8c9a-5dfcdcb36aaf" xlink:to="loc_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_019e64c7-5561-788f-83c9-3d99db9ac0bc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_019e64c7-5561-7908-b900-6a9a5c680b4e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e64c7-5561-7e07-8c9a-5dfcdcb36aaf" xlink:to="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_019e64c7-5561-7908-b900-6a9a5c680b4e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e64c7-5561-7e59-8f86-38991de62452" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/ACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSSScheduleofReclassificationoutofAccumulatedOtherComprehensiveIncomeDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#ACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSSScheduleofReclassificationoutofAccumulatedOtherComprehensiveIncomeDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/ACCUMULATEDOTHERCOMPREHENSIVEINCOMELOSSScheduleofReclassificationoutofAccumulatedOtherComprehensiveIncomeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e64c7-5561-713c-b970-12e1cfd3f461" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019e64c7-5561-7366-a35c-4b492f0de20e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e64c7-5561-713c-b970-12e1cfd3f461" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019e64c7-5561-7366-a35c-4b492f0de20e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_019e64c7-5561-7cd9-b5b9-520354e11a9e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019e64c7-5561-7366-a35c-4b492f0de20e" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_019e64c7-5561-7cd9-b5b9-520354e11a9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_019e64c7-5561-7cd9-b5b9-520354e11a9e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_019e64c7-5561-7cd9-b5b9-520354e11a9e" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_019e64c7-5561-7cd9-b5b9-520354e11a9e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_019e64c7-5561-72ce-b700-179e9e349c1d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_019e64c7-5561-7cd9-b5b9-520354e11a9e" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_019e64c7-5561-72ce-b700-179e9e349c1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_019e64c7-5561-7102-834a-cd7f5327f0b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_019e64c7-5561-72ce-b700-179e9e349c1d" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_019e64c7-5561-7102-834a-cd7f5327f0b5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e64c7-5561-7762-af27-de162f84c3a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019e64c7-5561-7366-a35c-4b492f0de20e" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e64c7-5561-7762-af27-de162f84c3a2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64c7-5561-7762-af27-de162f84c3a2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64c7-5561-7762-af27-de162f84c3a2" xlink:to="loc_us-gaap_EquityComponentDomain_019e64c7-5561-7762-af27-de162f84c3a2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e64c7-5561-70f1-bd90-488ced98ea7a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e64c7-5561-7762-af27-de162f84c3a2" xlink:to="loc_us-gaap_EquityComponentDomain_019e64c7-5561-70f1-bd90-488ced98ea7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_019e64c7-5561-7642-a381-5d6289ec9f61" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64c7-5561-70f1-bd90-488ced98ea7a" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_019e64c7-5561-7642-a381-5d6289ec9f61" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_019e64c7-5561-75b9-900f-03dad37430ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e64c7-5561-70f1-bd90-488ced98ea7a" xlink:to="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_019e64c7-5561-75b9-900f-03dad37430ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_019e64c7-5561-7f9c-b5f3-70a6fc0089fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e64c7-5561-713c-b970-12e1cfd3f461" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_019e64c7-5561-7f9c-b5f3-70a6fc0089fb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtAndEquitySecuritiesGainLoss_019e64c7-5561-7021-9cc8-fe9ba22c88ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtAndEquitySecuritiesGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e64c7-5561-713c-b970-12e1cfd3f461" xlink:to="loc_us-gaap_DebtAndEquitySecuritiesGainLoss_019e64c7-5561-7021-9cc8-fe9ba22c88ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019e64c7-5561-7f35-9af1-a2527317e4fa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e64c7-5561-713c-b970-12e1cfd3f461" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019e64c7-5561-7f35-9af1-a2527317e4fa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnContractTermination_019e64c7-5561-7d00-aec7-473ab6d7e54d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnContractTermination"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e64c7-5561-713c-b970-12e1cfd3f461" xlink:to="loc_us-gaap_GainLossOnContractTermination_019e64c7-5561-7d00-aec7-473ab6d7e54d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e64c7-5561-7cd7-9715-1a83ca1cf128" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e64c7-5561-713c-b970-12e1cfd3f461" xlink:to="loc_us-gaap_NetIncomeLoss_019e64c7-5561-7cd7-9715-1a83ca1cf128" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/EARNINGSPERCOMMONSHAREBasicandDilutedEarningsperCommonShareDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#EARNINGSPERCOMMONSHAREBasicandDilutedEarningsperCommonShareDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/EARNINGSPERCOMMONSHAREBasicandDilutedEarningsperCommonShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_019e64c7-5561-701e-8b91-785c99f7c45f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_019e64c7-5561-701e-8b91-785c99f7c45f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019e64c7-5561-7307-942a-0a079d68f6d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_019e64c7-5561-701e-8b91-785c99f7c45f" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019e64c7-5561-7307-942a-0a079d68f6d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e64c7-5561-7307-942a-0a079d68f6d4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019e64c7-5561-7307-942a-0a079d68f6d4" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e64c7-5561-7307-942a-0a079d68f6d4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e64c7-5561-77e3-a2b6-b006846c4fe6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019e64c7-5561-7307-942a-0a079d68f6d4" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e64c7-5561-77e3-a2b6-b006846c4fe6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_019e64c7-5561-760b-8adf-34b630fd926c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e64c7-5561-77e3-a2b6-b006846c4fe6" xlink:to="loc_us-gaap_EmployeeStockOptionMember_019e64c7-5561-760b-8adf-34b630fd926c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e64c7-5561-7458-b5d8-aa22897c4c5d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_us-gaap_NetIncomeLoss_019e64c7-5561-7458-b5d8-aa22897c4c5d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPreferredStockCash_019e64c7-5561-7d68-9fae-af9036f30fed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsPreferredStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_us-gaap_DividendsPreferredStockCash_019e64c7-5561-7d68-9fae-af9036f30fed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_EarningsLossBeforeDistributedAndUndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic_019e64c7-5561-701b-ade5-f87bfa28bdb4" xlink:href="msbi-20260630.xsd#msbi_EarningsLossBeforeDistributedAndUndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_msbi_EarningsLossBeforeDistributedAndUndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic_019e64c7-5561-701b-ade5-f87bfa28bdb4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStock_019e64c7-5561-7364-9d2a-faa6a3ced9a8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_us-gaap_DividendsCommonStock_019e64c7-5561-7364-9d2a-faa6a3ced9a8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsShareBasedCompensation_019e64c7-5561-7292-8cff-1113be5be396" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_us-gaap_DividendsShareBasedCompensation_019e64c7-5561-7292-8cff-1113be5be396" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic_019e64c7-5561-7f2f-80a3-f180e60f4501" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic_019e64c7-5561-7f2f-80a3-f180e60f4501" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_UndistributedEarningsToCommonShareholders_019e64c7-5561-770b-9e09-a1eca7e6eaa0" xlink:href="msbi-20260630.xsd#msbi_UndistributedEarningsToCommonShareholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_msbi_UndistributedEarningsToCommonShareholders_019e64c7-5561-770b-9e09-a1eca7e6eaa0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UndistributedEarningsAbstract_019e64c7-5561-7edc-a4fd-340ab45e0ea8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UndistributedEarningsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_us-gaap_UndistributedEarningsAbstract_019e64c7-5561-7edc-a4fd-340ab45e0ea8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStock_019e64c7-5561-712f-8e88-58265dcb526c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsCommonStock"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UndistributedEarningsLossAvailableToCommonShareholdersBasic_019e64c7-5561-73d3-936a-0e016461c2f0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UndistributedEarningsLossAvailableToCommonShareholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UndistributedEarningsAbstract_019e64c7-5561-7edc-a4fd-340ab45e0ea8" xlink:to="loc_us-gaap_UndistributedEarningsLossAvailableToCommonShareholdersBasic_019e64c7-5561-73d3-936a-0e016461c2f0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019e64c7-5561-74e0-b2a8-4146f1a560a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UndistributedEarningsAbstract_019e64c7-5561-7edc-a4fd-340ab45e0ea8" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019e64c7-5561-74e0-b2a8-4146f1a560a2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UndistributedEarningsDilutedAbstract_019e64c7-5561-7771-9192-79cdd4a0ae4a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UndistributedEarningsDilutedAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_us-gaap_UndistributedEarningsDilutedAbstract_019e64c7-5561-7771-9192-79cdd4a0ae4a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStock_019e64c7-5561-7b01-ae29-06845b8a33cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsCommonStock"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UndistributedEarningsLossAvailableToCommonShareholdersDiluted_019e64c7-5561-79cc-908b-d026c0ba0630" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UndistributedEarningsLossAvailableToCommonShareholdersDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UndistributedEarningsDilutedAbstract_019e64c7-5561-7771-9192-79cdd4a0ae4a" xlink:to="loc_us-gaap_UndistributedEarningsLossAvailableToCommonShareholdersDiluted_019e64c7-5561-79cc-908b-d026c0ba0630" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019e64c7-5561-75bf-8371-ee0b236cd78c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DilutiveSecuritiesAbstract_019e64c7-5561-7f03-a715-30e647101b68" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DilutiveSecuritiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UndistributedEarningsDilutedAbstract_019e64c7-5561-7771-9192-79cdd4a0ae4a" xlink:to="loc_us-gaap_DilutiveSecuritiesAbstract_019e64c7-5561-7f03-a715-30e647101b68" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UndistributedEarningsDiluted_019e64c7-5561-7a79-8c5c-4bd903837643" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UndistributedEarningsDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DilutiveSecuritiesAbstract_019e64c7-5561-7f03-a715-30e647101b68" xlink:to="loc_us-gaap_UndistributedEarningsDiluted_019e64c7-5561-7a79-8c5c-4bd903837643" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019e64c7-5561-7255-b59c-936bd620d8ba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UndistributedEarningsDilutedAbstract_019e64c7-5561-7771-9192-79cdd4a0ae4a" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019e64c7-5561-7255-b59c-936bd620d8ba" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019e64c7-5561-73df-8ed0-f0dfd451fda2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019e64c7-5561-73df-8ed0-f0dfd451fda2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_019e64c7-5561-76e1-b3ba-3872c6e475a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_019e64c7-5561-76e1-b3ba-3872c6e475a2" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e64c7-5561-7ed1-b374-e25c0294a5b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e64c7-5561-7ed1-b374-e25c0294a5b2" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_019e64c7-5561-7483-b145-cc4d944a89ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_us-gaap_EarningsPerShareBasic_019e64c7-5561-7483-b145-cc4d944a89ca" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_019e64c7-5561-7261-964a-340ce59672da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_us-gaap_EarningsPerShareDiluted_019e64c7-5561-7261-964a-340ce59672da" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019e64c7-5561-7c0a-9985-3a8221479081" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e64c7-5561-7778-8bed-77023f0c9d1d" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019e64c7-5561-7c0a-9985-3a8221479081" xlink:type="arc" order="14"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSRecurringandNonrecurringbasisDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#FAIRVALUEOFFINANCIALINSTRUMENTSRecurringandNonrecurringbasisDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSRecurringandNonrecurringbasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e64c7-5628-7961-9a1b-7c59f649be78" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e64c7-5561-797f-8f2b-b419745a0cd1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e64c7-5628-7961-9a1b-7c59f649be78" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e64c7-5561-797f-8f2b-b419745a0cd1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e64c7-5561-71d3-acbf-bf9d0b3ee543" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e64c7-5561-797f-8f2b-b419745a0cd1" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e64c7-5561-71d3-acbf-bf9d0b3ee543" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e64c7-5561-71d3-acbf-bf9d0b3ee543_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e64c7-5561-71d3-acbf-bf9d0b3ee543" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e64c7-5561-71d3-acbf-bf9d0b3ee543_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e64c7-5561-740f-991d-b6c05688ec24" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e64c7-5561-71d3-acbf-bf9d0b3ee543" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e64c7-5561-740f-991d-b6c05688ec24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_019e64c7-5561-76a2-a817-2abaf01e395c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e64c7-5561-740f-991d-b6c05688ec24" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_019e64c7-5561-76a2-a817-2abaf01e395c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_019e64c7-5561-7a76-a1b5-74105b8a1f26" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsNonrecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e64c7-5561-740f-991d-b6c05688ec24" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_019e64c7-5561-7a76-a1b5-74105b8a1f26" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e64c7-5561-7651-8f3b-a9b78e2bea99" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e64c7-5561-797f-8f2b-b419745a0cd1" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e64c7-5561-7651-8f3b-a9b78e2bea99" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5561-7651-8f3b-a9b78e2bea99_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e64c7-5561-7651-8f3b-a9b78e2bea99" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5561-7651-8f3b-a9b78e2bea99_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7f02-bed3-3d57ea1e2ba5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e64c7-5561-7651-8f3b-a9b78e2bea99" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7f02-bed3-3d57ea1e2ba5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019e64c7-5628-78e5-8547-78dd5728efdf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7f02-bed3-3d57ea1e2ba5" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019e64c7-5628-78e5-8547-78dd5728efdf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019e64c7-5628-728c-80ca-4dcce91393fc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7f02-bed3-3d57ea1e2ba5" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019e64c7-5628-728c-80ca-4dcce91393fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019e64c7-5628-7ceb-975c-1b49819058dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7f02-bed3-3d57ea1e2ba5" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019e64c7-5628-7ceb-975c-1b49819058dc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5628-79a0-963f-7b3e564bead8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e64c7-5561-797f-8f2b-b419745a0cd1" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5628-79a0-963f-7b3e564bead8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-79a0-963f-7b3e564bead8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5628-79a0-963f-7b3e564bead8" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-79a0-963f-7b3e564bead8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-707a-bde7-97123b3d7c57" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5628-79a0-963f-7b3e564bead8" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-707a-bde7-97123b3d7c57" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_019e64c7-5628-75d8-8c7d-59b14f8f6738" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-707a-bde7-97123b3d7c57" xlink:to="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_019e64c7-5628-75d8-8c7d-59b14f8f6738" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019e64c7-5628-75a3-9da1-7e9afbb6a884" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-707a-bde7-97123b3d7c57" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019e64c7-5628-75a3-9da1-7e9afbb6a884" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_NonagencyMortgageBackedSecuritiesMember_019e64c7-5628-7dd1-986a-70f02db86d24" xlink:href="msbi-20260630.xsd#msbi_NonagencyMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-707a-bde7-97123b3d7c57" xlink:to="loc_msbi_NonagencyMortgageBackedSecuritiesMember_019e64c7-5628-7dd1-986a-70f02db86d24" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_StudentLoanAssetBackedMember_019e64c7-5628-79ec-86a9-57877fb187a2" xlink:href="msbi-20260630.xsd#msbi_StudentLoanAssetBackedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-707a-bde7-97123b3d7c57" xlink:to="loc_msbi_StudentLoanAssetBackedMember_019e64c7-5628-79ec-86a9-57877fb187a2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e64c7-5628-7f84-89bc-fe96ab648caa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-707a-bde7-97123b3d7c57" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e64c7-5628-7f84-89bc-fe96ab648caa" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralizedLoanObligationsMember_019e64c7-5628-7dc3-9806-957a6b160524" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralizedLoanObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-707a-bde7-97123b3d7c57" xlink:to="loc_us-gaap_CollateralizedLoanObligationsMember_019e64c7-5628-7dc3-9806-957a6b160524" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_019e64c7-5628-77fc-ae9b-bd131cab69e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-707a-bde7-97123b3d7c57" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_019e64c7-5628-77fc-ae9b-bd131cab69e6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialLoanMember_019e64c7-5628-70ae-8eda-ddede3d3958c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-707a-bde7-97123b3d7c57" xlink:to="loc_us-gaap_CommercialLoanMember_019e64c7-5628-70ae-8eda-ddede3d3958c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_019e64c7-5628-734f-81d5-a21cfa159884" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-707a-bde7-97123b3d7c57" xlink:to="loc_us-gaap_CommercialRealEstateMember_019e64c7-5628-734f-81d5-a21cfa159884" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019f6596-dd56-70a1-b8b7-6a24d7f7c8c8" xlink:href="msbi-20260630.xsd#msbi_ConstructionAndLandDevelopmentLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-707a-bde7-97123b3d7c57" xlink:to="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019f6596-dd56-70a1-b8b7-6a24d7f7c8c8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageMember_019e64c7-5628-7975-8a57-26394e78f45d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialMortgageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-707a-bde7-97123b3d7c57" xlink:to="loc_us-gaap_ResidentialMortgageMember_019e64c7-5628-7975-8a57-26394e78f45d" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract_019e64c7-5628-733e-9574-22ce6688bb0a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e64c7-5628-7961-9a1b-7c59f649be78" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract_019e64c7-5628-733e-9574-22ce6688bb0a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e64c7-5628-78a4-9926-e3e2680a7990" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract_019e64c7-5628-733e-9574-22ce6688bb0a" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e64c7-5628-78a4-9926-e3e2680a7990" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e64c7-5628-7259-a072-857700d60dd5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e64c7-5628-78a4-9926-e3e2680a7990" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e64c7-5628-7259-a072-857700d60dd5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNi_019e64c7-5628-767a-b6c0-0274ec08bb4a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFvNi"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e64c7-5628-78a4-9926-e3e2680a7990" xlink:to="loc_us-gaap_EquitySecuritiesFvNi_019e64c7-5628-767a-b6c0-0274ec08bb4a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansHeldForSaleFairValueDisclosure_019e64c7-5628-7dff-9ece-2313b694fb36" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansHeldForSaleFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e64c7-5628-78a4-9926-e3e2680a7990" xlink:to="loc_us-gaap_LoansHeldForSaleFairValueDisclosure_019e64c7-5628-7dff-9ece-2313b694fb36" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_CreditEnhancementAssetFairValueDisclosure_019e64c7-5628-7926-9e5a-99cfc2ac84fe" xlink:href="msbi-20260630.xsd#msbi_CreditEnhancementAssetFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e64c7-5628-78a4-9926-e3e2680a7990" xlink:to="loc_msbi_CreditEnhancementAssetFairValueDisclosure_019e64c7-5628-7926-9e5a-99cfc2ac84fe" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_019e64c7-5628-72ea-8cfd-6efc0472b1d5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e64c7-5628-78a4-9926-e3e2680a7990" xlink:to="loc_us-gaap_DerivativeAssets_019e64c7-5628-72ea-8cfd-6efc0472b1d5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration_019e64c7-5628-7378-8db2-c6ca3aadcae8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeAssets_019e64c7-5628-72ea-8cfd-6efc0472b1d5" xlink:to="loc_us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration_019e64c7-5628-7378-8db2-c6ca3aadcae8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_019e64c7-5628-7cff-92c4-d290444b5e2f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e64c7-5628-78a4-9926-e3e2680a7990" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_019e64c7-5628-7cff-92c4-d290444b5e2f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e64c7-5628-73df-8822-5e9621afc657" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract_019e64c7-5628-733e-9574-22ce6688bb0a" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e64c7-5628-73df-8822-5e9621afc657" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradingLiabilitiesFairValueDisclosure_019e64c7-5628-7908-9b55-3d274010ebfa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TradingLiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e64c7-5628-73df-8822-5e9621afc657" xlink:to="loc_us-gaap_TradingLiabilitiesFairValueDisclosure_019e64c7-5628-7908-9b55-3d274010ebfa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialLiabilitiesFairValueDisclosure_019e64c7-5628-76b1-9738-aa105170279a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialLiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e64c7-5628-73df-8822-5e9621afc657" xlink:to="loc_us-gaap_FinancialLiabilitiesFairValueDisclosure_019e64c7-5628-76b1-9738-aa105170279a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FairValueAssetsLiabilitiesAndStockholdersEquityMeasuredOnNonRecurringBasisAbstract_019e64c7-5628-7d32-aba0-e18b5daa3970" xlink:href="msbi-20260630.xsd#msbi_FairValueAssetsLiabilitiesAndStockholdersEquityMeasuredOnNonRecurringBasisAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract_019e64c7-5628-733e-9574-22ce6688bb0a" xlink:to="loc_msbi_FairValueAssetsLiabilitiesAndStockholdersEquityMeasuredOnNonRecurringBasisAbstract_019e64c7-5628-7d32-aba0-e18b5daa3970" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FinancingReceivableIndividuallyEvaluatedForCreditLossAverageRecordedInvestment_019e64c7-5628-79c2-a23f-8b1b0a132d9a" xlink:href="msbi-20260630.xsd#msbi_FinancingReceivableIndividuallyEvaluatedForCreditLossAverageRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_msbi_FairValueAssetsLiabilitiesAndStockholdersEquityMeasuredOnNonRecurringBasisAbstract_019e64c7-5628-7d32-aba0-e18b5daa3970" xlink:to="loc_msbi_FinancingReceivableIndividuallyEvaluatedForCreditLossAverageRecordedInvestment_019e64c7-5628-79c2-a23f-8b1b0a132d9a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_RealEstateOwnedOtherFairValueDisclosure_019e64c7-5628-76fd-90e4-cefdf2bea20d" xlink:href="msbi-20260630.xsd#msbi_RealEstateOwnedOtherFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_msbi_FairValueAssetsLiabilitiesAndStockholdersEquityMeasuredOnNonRecurringBasisAbstract_019e64c7-5628-7d32-aba0-e18b5daa3970" xlink:to="loc_msbi_RealEstateOwnedOtherFairValueDisclosure_019e64c7-5628-76fd-90e4-cefdf2bea20d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FairValueGainsLossesRecognizedOnAssetsMeasuredOnNonRecurringBasisAbstract_019e64c7-5628-74de-8f08-43cd40469699" xlink:href="msbi-20260630.xsd#msbi_FairValueGainsLossesRecognizedOnAssetsMeasuredOnNonRecurringBasisAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract_019e64c7-5628-733e-9574-22ce6688bb0a" xlink:to="loc_msbi_FairValueGainsLossesRecognizedOnAssetsMeasuredOnNonRecurringBasisAbstract_019e64c7-5628-74de-8f08-43cd40469699" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FairValueGainsLossesRecognizedOnAssetsMeasuredOnNonRecurringBasisImpairedLoans_019e64c7-5628-7c39-afcf-6d0d5444bc0d" xlink:href="msbi-20260630.xsd#msbi_FairValueGainsLossesRecognizedOnAssetsMeasuredOnNonRecurringBasisImpairedLoans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_msbi_FairValueGainsLossesRecognizedOnAssetsMeasuredOnNonRecurringBasisAbstract_019e64c7-5628-74de-8f08-43cd40469699" xlink:to="loc_msbi_FairValueGainsLossesRecognizedOnAssetsMeasuredOnNonRecurringBasisImpairedLoans_019e64c7-5628-7c39-afcf-6d0d5444bc0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FairValueGainsLossesRecognizedOnAssetsMeasuredOnNonRecurringBasis_019e64c7-5628-77f0-83dc-f3391c608a38" xlink:href="msbi-20260630.xsd#msbi_FairValueGainsLossesRecognizedOnAssetsMeasuredOnNonRecurringBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_msbi_FairValueGainsLossesRecognizedOnAssetsMeasuredOnNonRecurringBasisAbstract_019e64c7-5628-74de-8f08-43cd40469699" xlink:to="loc_msbi_FairValueGainsLossesRecognizedOnAssetsMeasuredOnNonRecurringBasis_019e64c7-5628-77f0-83dc-f3391c608a38" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSQuantitativeInformationDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#FAIRVALUEOFFINANCIALINSTRUMENTSQuantitativeInformationDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSQuantitativeInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019e64c7-5628-7e1c-96e6-edb37b0d0bf0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e64c7-5628-7065-9e80-c0b00f92b7d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019e64c7-5628-7e1c-96e6-edb37b0d0bf0" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e64c7-5628-7065-9e80-c0b00f92b7d2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e64c7-5628-755e-a5c4-94f14d31e030" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e64c7-5628-7065-9e80-c0b00f92b7d2" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e64c7-5628-755e-a5c4-94f14d31e030" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-755e-a5c4-94f14d31e030_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e64c7-5628-755e-a5c4-94f14d31e030" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-755e-a5c4-94f14d31e030_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7924-96af-044028fcbb42" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e64c7-5628-755e-a5c4-94f14d31e030" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7924-96af-044028fcbb42" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019e64c7-5628-7c45-9e20-cbd7472ac280" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7924-96af-044028fcbb42" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019e64c7-5628-7c45-9e20-cbd7472ac280" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e64c7-5628-737c-8699-4ac37f7beb7c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e64c7-5628-7065-9e80-c0b00f92b7d2" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e64c7-5628-737c-8699-4ac37f7beb7c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e64c7-5628-737c-8699-4ac37f7beb7c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e64c7-5628-737c-8699-4ac37f7beb7c" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e64c7-5628-737c-8699-4ac37f7beb7c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e64c7-5628-7887-bf88-8fda73a9b4f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e64c7-5628-737c-8699-4ac37f7beb7c" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e64c7-5628-7887-bf88-8fda73a9b4f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_019e64c7-5628-74fa-8a0d-9bd2f1d38186" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsNonrecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e64c7-5628-7887-bf88-8fda73a9b4f1" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_019e64c7-5628-74fa-8a0d-9bd2f1d38186" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueAxis_019e64c7-5628-779d-a6ec-d8bf38b079a6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ValuationTechniqueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e64c7-5628-7065-9e80-c0b00f92b7d2" xlink:to="loc_us-gaap_ValuationTechniqueAxis_019e64c7-5628-779d-a6ec-d8bf38b079a6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_019e64c7-5628-779d-a6ec-d8bf38b079a6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationTechniqueAxis_019e64c7-5628-779d-a6ec-d8bf38b079a6" xlink:to="loc_us-gaap_ValuationTechniqueDomain_019e64c7-5628-779d-a6ec-d8bf38b079a6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_019e64c7-5628-7075-84a4-ed1a2f760e03" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationTechniqueAxis_019e64c7-5628-779d-a6ec-d8bf38b079a6" xlink:to="loc_us-gaap_ValuationTechniqueDomain_019e64c7-5628-7075-84a4-ed1a2f760e03" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueOptionPricingModelMember_019e64c7-5628-7f47-8a3f-45ffcc69a64e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ValuationTechniqueOptionPricingModelMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_019e64c7-5628-7075-84a4-ed1a2f760e03" xlink:to="loc_us-gaap_ValuationTechniqueOptionPricingModelMember_019e64c7-5628-7f47-8a3f-45ffcc69a64e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_019e64c7-5628-7769-8a28-12b87b432346" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e64c7-5628-7065-9e80-c0b00f92b7d2" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_019e64c7-5628-7769-8a28-12b87b432346" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_019e64c7-5628-7769-8a28-12b87b432346_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_019e64c7-5628-7769-8a28-12b87b432346" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_019e64c7-5628-7769-8a28-12b87b432346_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_019e64c7-5628-7c9f-b568-22512c0308cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_019e64c7-5628-7769-8a28-12b87b432346" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_019e64c7-5628-7c9f-b568-22512c0308cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_MeasurementInputDiscountRateForTypeOfPropertyAgeOfAppraisalAndCurrentStatusMember_019e64c7-5628-762f-9d7f-41884f223135" xlink:href="msbi-20260630.xsd#msbi_MeasurementInputDiscountRateForTypeOfPropertyAgeOfAppraisalAndCurrentStatusMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019e64c7-5628-7c9f-b568-22512c0308cf" xlink:to="loc_msbi_MeasurementInputDiscountRateForTypeOfPropertyAgeOfAppraisalAndCurrentStatusMember_019e64c7-5628-762f-9d7f-41884f223135" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e64c7-5628-72ed-944b-51bd3a04731c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e64c7-5628-7065-9e80-c0b00f92b7d2" xlink:to="loc_srt_RangeAxis_019e64c7-5628-72ed-944b-51bd3a04731c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e64c7-5628-72ed-944b-51bd3a04731c_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e64c7-5628-72ed-944b-51bd3a04731c" xlink:to="loc_srt_RangeMember_019e64c7-5628-72ed-944b-51bd3a04731c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e64c7-5628-7539-b411-e984e9c492cb" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e64c7-5628-72ed-944b-51bd3a04731c" xlink:to="loc_srt_RangeMember_019e64c7-5628-7539-b411-e984e9c492cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019e64c7-5628-764f-98df-157ef0193664" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e64c7-5628-7539-b411-e984e9c492cb" xlink:to="loc_srt_MinimumMember_019e64c7-5628-764f-98df-157ef0193664" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e64c7-5628-708e-9a89-d736bf13f0f0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e64c7-5628-7539-b411-e984e9c492cb" xlink:to="loc_srt_MaximumMember_019e64c7-5628-708e-9a89-d736bf13f0f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_WeightedAverageMember_019e64c7-5628-7932-88b2-bd6e7bb2ca05" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_WeightedAverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e64c7-5628-7539-b411-e984e9c492cb" xlink:to="loc_srt_WeightedAverageMember_019e64c7-5628-7932-88b2-bd6e7bb2ca05" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5628-7b2e-95bb-5312886035fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e64c7-5628-7065-9e80-c0b00f92b7d2" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5628-7b2e-95bb-5312886035fe" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-7b2e-95bb-5312886035fe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5628-7b2e-95bb-5312886035fe" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-7b2e-95bb-5312886035fe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-711a-906d-d836ec53e6d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e64c7-5628-7b2e-95bb-5312886035fe" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-711a-906d-d836ec53e6d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialLoanMember_019e64c7-5628-72c3-b831-df1c223781cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-711a-906d-d836ec53e6d6" xlink:to="loc_us-gaap_CommercialLoanMember_019e64c7-5628-72c3-b831-df1c223781cf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_019e64c7-5628-7775-92fc-a4e029a562ad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-711a-906d-d836ec53e6d6" xlink:to="loc_us-gaap_CommercialRealEstateMember_019e64c7-5628-7775-92fc-a4e029a562ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019f6598-5a5b-7f30-9d29-5bbc97d1a7e0" xlink:href="msbi-20260630.xsd#msbi_ConstructionAndLandDevelopmentLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-711a-906d-d836ec53e6d6" xlink:to="loc_msbi_ConstructionAndLandDevelopmentLoanMember_019f6598-5a5b-7f30-9d29-5bbc97d1a7e0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageMember_019e64c7-5628-72bf-8a30-b6725b177e54" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialMortgageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-711a-906d-d836ec53e6d6" xlink:to="loc_us-gaap_ResidentialMortgageMember_019e64c7-5628-72bf-8a30-b6725b177e54" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherRealEstateLoansLoanReceivablesMember_019e64c7-5628-7436-b534-dc221c2012c2" xlink:href="msbi-20260630.xsd#msbi_OtherRealEstateLoansLoanReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e64c7-5628-711a-906d-d836ec53e6d6" xlink:to="loc_msbi_OtherRealEstateLoansLoanReceivablesMember_019e64c7-5628-7436-b534-dc221c2012c2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_FinancingReceivableIndividuallyEvaluatedForCreditLossAverageRecordedInvestment_019e64c7-5628-772f-9277-0576f5e217a7" xlink:href="msbi-20260630.xsd#msbi_FinancingReceivableIndividuallyEvaluatedForCreditLossAverageRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019e64c7-5628-7e1c-96e6-edb37b0d0bf0" xlink:to="loc_msbi_FinancingReceivableIndividuallyEvaluatedForCreditLossAverageRecordedInvestment_019e64c7-5628-772f-9277-0576f5e217a7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_ImpairedFinancingReceivableMeasurementInput_019e64c7-5628-7ce1-a11e-e80880ad7e7a" xlink:href="msbi-20260630.xsd#msbi_ImpairedFinancingReceivableMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019e64c7-5628-7e1c-96e6-edb37b0d0bf0" xlink:to="loc_msbi_ImpairedFinancingReceivableMeasurementInput_019e64c7-5628-7ce1-a11e-e80880ad7e7a" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSFairvalueoptionandgainsandlossesfromfairvaluechangesDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#FAIRVALUEOFFINANCIALINSTRUMENTSFairvalueoptionandgainsandlossesfromfairvaluechangesDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSFairvalueoptionandgainsandlossesfromfairvaluechangesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019e64c7-5628-7557-8741-43d1004b1109" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueOptionQuantitativeDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueOptionQuantitativeDisclosuresTable_019e64c7-5628-7d6a-8284-6783846f04cc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueOptionQuantitativeDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019e64c7-5628-7557-8741-43d1004b1109" xlink:to="loc_us-gaap_FairValueOptionQuantitativeDisclosuresTable_019e64c7-5628-7d6a-8284-6783846f04cc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5628-713f-aeb7-a25fc140222b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresTable_019e64c7-5628-7d6a-8284-6783846f04cc" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5628-713f-aeb7-a25fc140222b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5628-713f-aeb7-a25fc140222b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5628-713f-aeb7-a25fc140222b" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5628-713f-aeb7-a25fc140222b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5628-78b0-ab0d-fe3c69a48c33" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e64c7-5628-713f-aeb7-a25fc140222b" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5628-78b0-ab0d-fe3c69a48c33" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5628-720e-b218-2b5175fd9517" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e64c7-5628-78b0-ab0d-fe3c69a48c33" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_019e64c7-5628-720e-b218-2b5175fd9517" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansHeldForSaleFairValueDisclosure_019e64c7-5628-72b4-a63e-a4eb96442ed5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansHeldForSaleFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019e64c7-5628-7557-8741-43d1004b1109" xlink:to="loc_us-gaap_LoansHeldForSaleFairValueDisclosure_019e64c7-5628-72b4-a63e-a4eb96442ed5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueOptionLoansHeldAsAssetsAggregateDifference_019e64c7-5628-771b-981e-8b5ac6b04d7b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueOptionLoansHeldAsAssetsAggregateDifference"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019e64c7-5628-7557-8741-43d1004b1109" xlink:to="loc_us-gaap_FairValueOptionLoansHeldAsAssetsAggregateDifference_019e64c7-5628-771b-981e-8b5ac6b04d7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansReceivableHeldForSaleAmount_019e64c7-5628-744b-ad94-0fc78c9acec9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansReceivableHeldForSaleAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019e64c7-5628-7557-8741-43d1004b1109" xlink:to="loc_us-gaap_LoansReceivableHeldForSaleAmount_019e64c7-5628-744b-ad94-0fc78c9acec9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivablesHeldForSaleAmountAbstract_019e64c7-5628-793f-93bd-833f19f741ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivablesHeldForSaleAmountAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019e64c7-5628-7557-8741-43d1004b1109" xlink:to="loc_us-gaap_ReceivablesHeldForSaleAmountAbstract_019e64c7-5628-793f-93bd-833f19f741ed" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueOptionChangesInFairValueGainLoss1_019e64c7-5628-7901-bc6f-0f8490b08b45" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueOptionChangesInFairValueGainLoss1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivablesHeldForSaleAmountAbstract_019e64c7-5628-793f-93bd-833f19f741ed" xlink:to="loc_us-gaap_FairValueOptionChangesInFairValueGainLoss1_019e64c7-5628-7901-bc6f-0f8490b08b45" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSCarryingvaluesandfairvalueDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#FAIRVALUEOFFINANCIALINSTRUMENTSCarryingvaluesandfairvalueDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSCarryingvaluesandfairvalueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e64c7-5628-770c-831d-7e607fae1253" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e64c7-5628-70b9-9f63-e69a7b10c18f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e64c7-5628-770c-831d-7e607fae1253" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e64c7-5628-70b9-9f63-e69a7b10c18f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_019e64c7-5628-7030-8f39-17ca9b68ba26" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e64c7-5628-70b9-9f63-e69a7b10c18f" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_019e64c7-5628-7030-8f39-17ca9b68ba26" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e64c7-5628-7030-8f39-17ca9b68ba26_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019e64c7-5628-7030-8f39-17ca9b68ba26" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e64c7-5628-7030-8f39-17ca9b68ba26_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019e64c7-5628-702e-bcfc-5eae57c090b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019e64c7-5628-7030-8f39-17ca9b68ba26" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019e64c7-5628-702e-bcfc-5eae57c090b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e64c7-5628-7a89-aac8-02a1e27463b3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019e64c7-5628-702e-bcfc-5eae57c090b1" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e64c7-5628-7a89-aac8-02a1e27463b3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019e64c7-5628-788a-adbb-8246bdc941f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e64c7-5628-7a89-aac8-02a1e27463b3" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019e64c7-5628-788a-adbb-8246bdc941f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019e64c7-5628-725f-a103-2c6523f9b30f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e64c7-5628-7a89-aac8-02a1e27463b3" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019e64c7-5628-725f-a103-2c6523f9b30f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e64c7-5628-7386-918e-65e4e841d9e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e64c7-5628-70b9-9f63-e69a7b10c18f" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e64c7-5628-7386-918e-65e4e841d9e5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7386-918e-65e4e841d9e5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e64c7-5628-7386-918e-65e4e841d9e5" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7386-918e-65e4e841d9e5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7f3c-b36a-287279b3ee11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e64c7-5628-7386-918e-65e4e841d9e5" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7f3c-b36a-287279b3ee11" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019e64c7-5628-7c10-8764-48fc35a0c7b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7f3c-b36a-287279b3ee11" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019e64c7-5628-7c10-8764-48fc35a0c7b8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019e64c7-5628-7b8b-91c3-58acc8278ac3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7f3c-b36a-287279b3ee11" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019e64c7-5628-7b8b-91c3-58acc8278ac3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019e64c7-5628-751d-9089-48416ec184b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e64c7-5628-7f3c-b36a-287279b3ee11" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019e64c7-5628-751d-9089-48416ec184b5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e64c7-5628-753f-aa43-098146b5779a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e64c7-5628-770c-831d-7e607fae1253" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e64c7-5628-753f-aa43-098146b5779a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019e64c7-5628-74d3-97c2-774b0f7ea4de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e64c7-5628-753f-aa43-098146b5779a" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019e64c7-5628-74d3-97c2-774b0f7ea4de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalFundsSoldAndSecuritiesBorrowedOrPurchasedUnderAgreementsToResellFairValueDisclosure_019e64c7-5628-7b8e-9250-5953c784dd1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalFundsSoldAndSecuritiesBorrowedOrPurchasedUnderAgreementsToResellFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e64c7-5628-753f-aa43-098146b5779a" xlink:to="loc_us-gaap_FederalFundsSoldAndSecuritiesBorrowedOrPurchasedUnderAgreementsToResellFairValueDisclosure_019e64c7-5628-7b8e-9250-5953c784dd1b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansReceivableFairValueDisclosure_019e64c7-5628-7fd5-849d-a59d89e2b2b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e64c7-5628-753f-aa43-098146b5779a" xlink:to="loc_us-gaap_LoansReceivableFairValueDisclosure_019e64c7-5628-7fd5-849d-a59d89e2b2b9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestReceivable_019e64c7-5628-7848-b56d-988200b55e21" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e64c7-5628-753f-aa43-098146b5779a" xlink:to="loc_us-gaap_InterestReceivable_019e64c7-5628-7848-b56d-988200b55e21" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e64c7-5628-7754-a3b4-14ff87246526" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e64c7-5628-770c-831d-7e607fae1253" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e64c7-5628-7754-a3b4-14ff87246526" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepositsFairValueDisclosure_019e64c7-5628-738c-bd97-3395e235649e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepositsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e64c7-5628-7754-a3b4-14ff87246526" xlink:to="loc_us-gaap_DepositsFairValueDisclosure_019e64c7-5628-738c-bd97-3395e235649e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShorttermDebtFairValue_019e64c7-5628-765f-b04c-a14bb3bd325a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShorttermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e64c7-5628-7754-a3b4-14ff87246526" xlink:to="loc_us-gaap_ShorttermDebtFairValue_019e64c7-5628-765f-b04c-a14bb3bd325a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure_019e64c7-5628-7dab-bd90-b4f9d22c79cc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e64c7-5628-7754-a3b4-14ff87246526" xlink:to="loc_us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure_019e64c7-5628-7dab-bd90-b4f9d22c79cc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations_019e64c7-5628-7384-82e3-f1b0cb054d19" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e64c7-5628-7754-a3b4-14ff87246526" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations_019e64c7-5628-7384-82e3-f1b0cb054d19" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust_019e64c7-5628-7f4d-a442-242686d1bd2b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e64c7-5628-7754-a3b4-14ff87246526" xlink:to="loc_us-gaap_JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust_019e64c7-5628-7f4d-a442-242686d1bd2b" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/COMMITMENTSCONTINGENCIESANDCREDITRISKDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#COMMITMENTSCONTINGENCIESANDCREDITRISKDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/COMMITMENTSCONTINGENCIESANDCREDITRISKDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_019e64c7-5628-76ad-90f8-6ba58ba75c1d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_019e64c7-5628-7dc5-9153-4bbb5a2a8a16" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_019e64c7-5628-76ad-90f8-6ba58ba75c1d" xlink:to="loc_us-gaap_LossContingenciesTable_019e64c7-5628-7dc5-9153-4bbb5a2a8a16" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_019e64c7-5628-7876-b94f-09b193c25c15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019e64c7-5628-7dc5-9153-4bbb5a2a8a16" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_019e64c7-5628-7876-b94f-09b193c25c15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_019e64c7-5628-7876-b94f-09b193c25c15_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_019e64c7-5628-7876-b94f-09b193c25c15" xlink:to="loc_us-gaap_LossContingencyNatureDomain_019e64c7-5628-7876-b94f-09b193c25c15_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_019e64c7-5628-72cf-9428-cc4fd1dfe42a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_019e64c7-5628-7876-b94f-09b193c25c15" xlink:to="loc_us-gaap_LossContingencyNatureDomain_019e64c7-5628-72cf-9428-cc4fd1dfe42a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsToExtendCreditMember_019e64c7-5628-7595-9cd6-0f978e45bb6e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommitmentsToExtendCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_019e64c7-5628-72cf-9428-cc4fd1dfe42a" xlink:to="loc_us-gaap_CommitmentsToExtendCreditMember_019e64c7-5628-7595-9cd6-0f978e45bb6e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialStandbyLetterOfCreditMember_019e64c7-5628-7abc-81b5-a45633e06c0c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialStandbyLetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_019e64c7-5628-72cf-9428-cc4fd1dfe42a" xlink:to="loc_us-gaap_FinancialStandbyLetterOfCreditMember_019e64c7-5628-7abc-81b5-a45633e06c0c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_019e64c7-5628-724c-80f7-d8f397d36bc3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingencyEstimateOfPossibleLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019e64c7-5628-76ad-90f8-6ba58ba75c1d" xlink:to="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_019e64c7-5628-724c-80f7-d8f397d36bc3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_LoanCommitments_019e64c7-5628-7f71-9119-6d1c0f1de3c6" xlink:href="msbi-20260630.xsd#msbi_LoanCommitments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019e64c7-5628-76ad-90f8-6ba58ba75c1d" xlink:to="loc_msbi_LoanCommitments_019e64c7-5628-7f71-9119-6d1c0f1de3c6" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/SEGMENTINFORMATIONDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#SEGMENTINFORMATIONDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/SEGMENTINFORMATIONDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e64c7-5628-7320-99f7-3df47d4bd2b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e64c7-5628-7320-99f7-3df47d4bd2b9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019e64c7-5628-78a7-962e-b4e5aaaea656" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e64c7-5628-7320-99f7-3df47d4bd2b9" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019e64c7-5628-78a7-962e-b4e5aaaea656" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e64c7-5628-78a7-962e-b4e5aaaea656_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e64c7-5628-78a7-962e-b4e5aaaea656" xlink:to="loc_us-gaap_SegmentDomain_019e64c7-5628-78a7-962e-b4e5aaaea656_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e64c7-5628-78b4-bb92-81f7a5077607" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e64c7-5628-78a7-962e-b4e5aaaea656" xlink:to="loc_us-gaap_SegmentDomain_019e64c7-5628-78b4-bb92-81f7a5077607" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_BankingSegmentMember_019e64c7-5628-730e-8039-e0b1e7a12e4f" xlink:href="msbi-20260630.xsd#msbi_BankingSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e64c7-5628-78b4-bb92-81f7a5077607" xlink:to="loc_msbi_BankingSegmentMember_019e64c7-5628-730e-8039-e0b1e7a12e4f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_WealthManagementMember_019e64c7-5628-7f51-8c5e-f3df7953d150" xlink:href="msbi-20260630.xsd#msbi_WealthManagementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e64c7-5628-78b4-bb92-81f7a5077607" xlink:to="loc_msbi_WealthManagementMember_019e64c7-5628-7f51-8c5e-f3df7953d150" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateMember_019e64c7-5628-7f05-8901-f889ad0965f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e64c7-5628-78b4-bb92-81f7a5077607" xlink:to="loc_us-gaap_CorporateMember_019e64c7-5628-7f05-8901-f889ad0965f3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeOperating_019e64c7-5628-7b54-8df5-0047de380433" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_InterestIncomeOperating_019e64c7-5628-7b54-8df5-0047de380433" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseOperating_019e64c7-5628-7412-af03-31c770426277" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_InterestExpenseOperating_019e64c7-5628-7412-af03-31c770426277" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_019e64c7-5628-7cce-8bb7-be7c7da52108" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_019e64c7-5628-7cce-8bb7-be7c7da52108" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForLoanLeaseAndOtherLosses_019e64c7-5628-7e8c-b1ab-e61998e8fb4f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProvisionForLoanLeaseAndOtherLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_ProvisionForLoanLeaseAndOtherLosses_019e64c7-5628-7e8c-b1ab-e61998e8fb4f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_WealthManagementRevenue_019e64c7-5628-74b5-bd83-0c5629b0d38f" xlink:href="msbi-20260630.xsd#msbi_WealthManagementRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_msbi_WealthManagementRevenue_019e64c7-5628-74b5-bd83-0c5629b0d38f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_NoninterestIncomeOtherAdjusted_019e64c7-5628-74bc-b2a7-14e664823eaa" xlink:href="msbi-20260630.xsd#msbi_NoninterestIncomeOtherAdjusted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_msbi_NoninterestIncomeOtherAdjusted_019e64c7-5628-74bc-b2a7-14e664823eaa" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestIncome_019e64c7-5628-78c9-9f8d-69bc6442ea0c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_NoninterestIncome_019e64c7-5628-78c9-9f8d-69bc6442ea0c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LaborAndRelatedExpense_019e64c7-5628-7729-b752-aef25ce1e062" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LaborAndRelatedExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_LaborAndRelatedExpense_019e64c7-5628-7729-b752-aef25ce1e062" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_019e64c7-5628-790d-94bd-995e6ea731bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_Depreciation_019e64c7-5628-790d-94bd-995e6ea731bc" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_019e64c7-5628-7933-b86f-aef600ff20b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_019e64c7-5628-7933-b86f-aef600ff20b4" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_019e904d-0cb4-7d8b-9caf-41ed34520f1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_019e904d-0cb4-7d8b-9caf-41ed34520f1b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_NoninterestExpenseOtherAdjusted_019e64c7-5628-7928-892b-cb28c3a90676" xlink:href="msbi-20260630.xsd#msbi_NoninterestExpenseOtherAdjusted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_msbi_NoninterestExpenseOtherAdjusted_019e64c7-5628-7928-892b-cb28c3a90676" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestExpense_019e64c7-5628-78fc-812f-054d61c4d155" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_NoninterestExpense_019e64c7-5628-78fc-812f-054d61c4d155" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e64c7-5628-7cfb-9424-b45f8ab5e59a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e64c7-5628-7cfb-9424-b45f8ab5e59a" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019e64c7-5628-74e1-85fc-26aa6f65d177" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019e64c7-5628-74e1-85fc-26aa6f65d177" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e64c7-5628-7d2c-b32a-112149ba6d08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_NetIncomeLoss_019e64c7-5628-7d2c-b32a-112149ba6d08" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019e64c7-5628-74b6-9e57-5f00743ba804" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e64c7-5628-7a61-8635-284132faf611" xlink:to="loc_us-gaap_Assets_019e64c7-5628-74b6-9e57-5f00743ba804" xlink:type="arc" order="16"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.midlandsb.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSDetails" xlink:type="simple" xlink:href="msbi-20260630.xsd#REVENUEFROMCONTRACTSWITHCUSTOMERSDetails"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019e64c7-5628-7de3-9f1e-d8841a52c5d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019e64c7-5628-7a0b-b3db-64791f0a7bae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e64c7-5628-7de3-9f1e-d8841a52c5d0" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019e64c7-5628-7a0b-b3db-64791f0a7bae" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019e64c7-5628-757f-919f-521480a21a8b" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019e64c7-5628-7a0b-b3db-64791f0a7bae" xlink:to="loc_srt_ProductOrServiceAxis_019e64c7-5628-757f-919f-521480a21a8b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e64c7-5628-757f-919f-521480a21a8b_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019e64c7-5628-757f-919f-521480a21a8b" xlink:to="loc_srt_ProductsAndServicesDomain_019e64c7-5628-757f-919f-521480a21a8b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e64c7-5628-73e5-813d-d71886780e6d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019e64c7-5628-757f-919f-521480a21a8b" xlink:to="loc_srt_ProductsAndServicesDomain_019e64c7-5628-73e5-813d-d71886780e6d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_AssetManagementMember_019e64c7-5628-78fa-b789-6db63e1c7ec0" xlink:href="msbi-20260630.xsd#msbi_AssetManagementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64c7-5628-73e5-813d-d71886780e6d" xlink:to="loc_msbi_AssetManagementMember_019e64c7-5628-78fa-b789-6db63e1c7ec0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentAdvisoryManagementAndAdministrativeServiceMember_019e64c7-5628-7f2f-8d3b-d4f2611cf465" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentAdvisoryManagementAndAdministrativeServiceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64c7-5628-73e5-813d-d71886780e6d" xlink:to="loc_us-gaap_InvestmentAdvisoryManagementAndAdministrativeServiceMember_019e64c7-5628-7f2f-8d3b-d4f2611cf465" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherWealthManagementRevenueMember_019e64c7-5628-7332-96d0-1775420fdbcb" xlink:href="msbi-20260630.xsd#msbi_OtherWealthManagementRevenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64c7-5628-73e5-813d-d71886780e6d" xlink:to="loc_msbi_OtherWealthManagementRevenueMember_019e64c7-5628-7332-96d0-1775420fdbcb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_NonsufficientFundFeesMember_019e64c7-5628-7788-b63b-e0e91d88aa3f" xlink:href="msbi-20260630.xsd#msbi_NonsufficientFundFeesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64c7-5628-73e5-813d-d71886780e6d" xlink:to="loc_msbi_NonsufficientFundFeesMember_019e64c7-5628-7788-b63b-e0e91d88aa3f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_OtherDepositAccountMember_019e64c7-5628-74cc-b0de-93f5342edb60" xlink:href="msbi-20260630.xsd#msbi_OtherDepositAccountMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64c7-5628-73e5-813d-d71886780e6d" xlink:to="loc_msbi_OtherDepositAccountMember_019e64c7-5628-74cc-b0de-93f5342edb60" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_InterchangeRevenuesMember_019e64c7-5628-7f56-a110-9ce77171855e" xlink:href="msbi-20260630.xsd#msbi_InterchangeRevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64c7-5628-73e5-813d-d71886780e6d" xlink:to="loc_msbi_InterchangeRevenuesMember_019e64c7-5628-7f56-a110-9ce77171855e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditCardMerchantDiscountMember_019e64c7-5628-7541-a83e-6bc64d9aa7f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditCardMerchantDiscountMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64c7-5628-73e5-813d-d71886780e6d" xlink:to="loc_us-gaap_CreditCardMerchantDiscountMember_019e64c7-5628-7541-a83e-6bc64d9aa7f7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ServiceOtherMember_019e64c7-5628-7345-a325-e18b8b5b82ee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e64c7-5628-73e5-813d-d71886780e6d" xlink:to="loc_us-gaap_ServiceOtherMember_019e64c7-5628-7345-a325-e18b8b5b82ee" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_019e64c7-5628-768a-a99d-72a64ec4f2c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e64c7-5628-7de3-9f1e-d8841a52c5d0" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_019e64c7-5628-768a-a99d-72a64ec4f2c5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_NoninterestIncomeOutOfScopeOfTopic606_019e64c7-5628-7207-a4a1-beb47f7eedc9" xlink:href="msbi-20260630.xsd#msbi_NoninterestIncomeOutOfScopeOfTopic606"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e64c7-5628-7de3-9f1e-d8841a52c5d0" xlink:to="loc_msbi_NoninterestIncomeOutOfScopeOfTopic606_019e64c7-5628-7207-a4a1-beb47f7eedc9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestIncome_019e64c7-5628-7f73-8af1-e89e87482672" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e64c7-5628-7de3-9f1e-d8841a52c5d0" xlink:to="loc_us-gaap_NoninterestIncome_019e64c7-5628-7f73-8af1-e89e87482672" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/srt/role/srt-eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-roles-2026.xsd#eedm1"/>
  <link:definitionLink xlink:role="http://fasb.org/srt/role/srt-eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet" xlink:type="arc" order="101"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesAndOtherLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedLiabilitiesAndOtherLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract" xlink:to="loc_us-gaap_AccruedLiabilitiesAndOtherLiabilities" xlink:type="arc" order="31"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#IndividualsOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllIndividualsMember" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#ecd_AllIndividualsMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_JeffreyG.LudwigMember_019ed43a-02a5-72b6-beb5-b77b7af1eea5" xlink:href="msbi-20260630.xsd#msbi_JeffreyG.LudwigMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_msbi_JeffreyG.LudwigMember_019ed43a-02a5-72b6-beb5-b77b7af1eea5" xlink:type="arc" order="2"/>
  </link:definitionLink>
</link:linkbase>
