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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019fcedf-45be-7b04-9385-2b9e633992c9,g:0443573e-1e06-43f1-812f-a9b9b6fd1873-->
<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.bannerbank.com/role/Cover" xlink:type="simple" xlink:href="banr-20261021.xsd#Cover"/>
  <link:definitionLink xlink:role="http://www.bannerbank.com/role/Cover" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationLineItems_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_019fcedf-45be-73a9-b575-5e8875a810d6" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_DocumentInformationTable_019fcedf-45be-73a9-b575-5e8875a810d6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationDocumentAxis_019fcedf-45be-77ec-8b42-2305b1d93a6f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationDocumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_019fcedf-45be-73a9-b575-5e8875a810d6" xlink:to="loc_dei_DocumentInformationDocumentAxis_019fcedf-45be-77ec-8b42-2305b1d93a6f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentDomain_019fcedf-45be-77ec-8b42-2305b1d93a6f_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_DocumentInformationDocumentAxis_019fcedf-45be-77ec-8b42-2305b1d93a6f" xlink:to="loc_dei_DocumentDomain_019fcedf-45be-77ec-8b42-2305b1d93a6f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentDomain_019fcedf-45be-79ec-941f-cb71a258cc52" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_DocumentInformationDocumentAxis_019fcedf-45be-77ec-8b42-2305b1d93a6f" xlink:to="loc_dei_DocumentDomain_019fcedf-45be-79ec-941f-cb71a258cc52" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019fcedf-45be-729f-9ad0-e6c2ca2fa99d" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_DocumentType_019fcedf-45be-729f-9ad0-e6c2ca2fa99d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019fcedf-45be-74d8-b90f-463f5cc6b7ec" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_DocumentPeriodEndDate_019fcedf-45be-74d8-b90f-463f5cc6b7ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019fcedf-45be-726e-b876-a4dd4d2b4eac" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_EntityRegistrantName_019fcedf-45be-726e-b876-a4dd4d2b4eac" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019fcedf-45be-7c15-8b35-69b4ce86203d" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019fcedf-45be-7c15-8b35-69b4ce86203d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019fcedf-45be-733c-9f63-62d52c2af428" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_EntityFileNumber_019fcedf-45be-733c-9f63-62d52c2af428" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019fcedf-45be-78d3-852e-f5062e2f9986" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_EntityTaxIdentificationNumber_019fcedf-45be-78d3-852e-f5062e2f9986" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019fcedf-45be-73d8-9e64-90dd44c8b919" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_EntityAddressAddressLine1_019fcedf-45be-73d8-9e64-90dd44c8b919" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019fcedf-45be-7f62-84cd-4f1d0078867c" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_EntityAddressCityOrTown_019fcedf-45be-7f62-84cd-4f1d0078867c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019fcedf-45be-7a4c-a33e-5cbe1692f8f7" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_EntityAddressStateOrProvince_019fcedf-45be-7a4c-a33e-5cbe1692f8f7" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019fcedf-45be-7eb0-b88f-7357f654e950" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_EntityAddressPostalZipCode_019fcedf-45be-7eb0-b88f-7357f654e950" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019fcedf-45be-7f62-8df0-55c319e944e9" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_CityAreaCode_019fcedf-45be-7f62-8df0-55c319e944e9" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019fcedf-45be-7c8d-aff7-5a1efdc9d4e9" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_LocalPhoneNumber_019fcedf-45be-7c8d-aff7-5a1efdc9d4e9" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_019fcedf-45be-725e-affb-cd5f86b33b4d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_WrittenCommunications"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_WrittenCommunications_019fcedf-45be-725e-affb-cd5f86b33b4d" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_019fcedf-45be-7fa7-ae69-014de610f2c5" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SolicitingMaterial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_SolicitingMaterial_019fcedf-45be-7fa7-ae69-014de610f2c5" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_019fcedf-45be-7120-bb53-11f83c53c7e0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_PreCommencementTenderOffer_019fcedf-45be-7120-bb53-11f83c53c7e0" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_019fcedf-45be-705e-b3fd-ed157e26d59e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_019fcedf-45be-705e-b3fd-ed157e26d59e" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019fcedf-45be-7d41-b32a-5f711e861999" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_Security12bTitle_019fcedf-45be-7d41-b32a-5f711e861999" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019fcedf-45be-70ff-8937-2f967f4110b3" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_TradingSymbol_019fcedf-45be-70ff-8937-2f967f4110b3" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019fcedf-45be-7ea1-bc84-88188d5bb9d4" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_SecurityExchangeName_019fcedf-45be-7ea1-bc84-88188d5bb9d4" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019fcedf-45be-7898-9d48-19b16f388311" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_EntityEmergingGrowthCompany_019fcedf-45be-7898-9d48-19b16f388311" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019fcedf-45be-7d21-90d4-ed530c262282" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_EntityCentralIndexKey_019fcedf-45be-7d21-90d4-ed530c262282" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019fcedf-45be-7cfe-aab3-8ff4083632bb" 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_019fcedf-45be-7292-bcc4-e1c4cb94e210" xlink:to="loc_dei_AmendmentFlag_019fcedf-45be-7cfe-aab3-8ff4083632bb" xlink:type="arc" order="21"/>
  </link:definitionLink>
</link:linkbase>
