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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019ff6f8-6ee6-7710-a537-f18927e60968,g:fa529ebc-f0e0-4427-9f95-8789aaddf41b-->
<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-20260811.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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_019ff6f8-6ee6-7043-93dd-ca25380006f4" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_DocumentInformationTable_019ff6f8-6ee6-7043-93dd-ca25380006f4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationDocumentAxis_019ff6f8-6ee6-7900-a176-646bb57680ae" 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_019ff6f8-6ee6-7043-93dd-ca25380006f4" xlink:to="loc_dei_DocumentInformationDocumentAxis_019ff6f8-6ee6-7900-a176-646bb57680ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentDomain_019ff6f8-6ee6-7900-a176-646bb57680ae_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_019ff6f8-6ee6-7900-a176-646bb57680ae" xlink:to="loc_dei_DocumentDomain_019ff6f8-6ee6-7900-a176-646bb57680ae_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentDomain_019ff6f8-6ee6-7fe7-a20a-188818873093" 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_019ff6f8-6ee6-7900-a176-646bb57680ae" xlink:to="loc_dei_DocumentDomain_019ff6f8-6ee6-7fe7-a20a-188818873093" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019ff6f8-6ee6-7e42-874f-264e7d05f24c" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_DocumentType_019ff6f8-6ee6-7e42-874f-264e7d05f24c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019ff6f8-6ee6-7ffd-a734-7fe04671295b" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_DocumentPeriodEndDate_019ff6f8-6ee6-7ffd-a734-7fe04671295b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019ff6f8-6ee6-72c1-9565-b5dfa3a2ef98" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_EntityRegistrantName_019ff6f8-6ee6-72c1-9565-b5dfa3a2ef98" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019ff6f8-6ee6-78f2-9043-b7156ccff931" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019ff6f8-6ee6-78f2-9043-b7156ccff931" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019ff6f8-6ee6-7516-a382-de3588a27346" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_EntityFileNumber_019ff6f8-6ee6-7516-a382-de3588a27346" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019ff6f8-6ee6-781b-98a6-f08f210ef6b5" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_EntityTaxIdentificationNumber_019ff6f8-6ee6-781b-98a6-f08f210ef6b5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019ff6f8-6ee6-72f5-821e-89451b2b96dc" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_EntityAddressAddressLine1_019ff6f8-6ee6-72f5-821e-89451b2b96dc" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019ff6f8-6ee6-77cb-b8e4-f0655ef856fc" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_EntityAddressCityOrTown_019ff6f8-6ee6-77cb-b8e4-f0655ef856fc" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019ff6f8-6ee6-7ba4-b2b2-0ff880ba136d" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_EntityAddressStateOrProvince_019ff6f8-6ee6-7ba4-b2b2-0ff880ba136d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019ff6f8-6ee6-7302-b4e9-caf1f93756c4" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_EntityAddressPostalZipCode_019ff6f8-6ee6-7302-b4e9-caf1f93756c4" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019ff6f8-6ee6-741b-96a6-385511dd43aa" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_CityAreaCode_019ff6f8-6ee6-741b-96a6-385511dd43aa" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019ff6f8-6ee6-784e-9665-a32ae4a3aef7" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_LocalPhoneNumber_019ff6f8-6ee6-784e-9665-a32ae4a3aef7" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_019ff6f8-6ee6-7211-8a2a-ad910245e1fa" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_WrittenCommunications_019ff6f8-6ee6-7211-8a2a-ad910245e1fa" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_019ff6f8-6ee6-7149-88c6-521fe013de32" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_SolicitingMaterial_019ff6f8-6ee6-7149-88c6-521fe013de32" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_019ff6f8-6ee6-788e-b34f-856f949385a9" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_PreCommencementTenderOffer_019ff6f8-6ee6-788e-b34f-856f949385a9" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_019ff6f8-6ee6-75dd-8cc8-0b78d84a1d45" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_019ff6f8-6ee6-75dd-8cc8-0b78d84a1d45" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019ff6f8-6ee6-7362-884b-685f85c5cf0a" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_Security12bTitle_019ff6f8-6ee6-7362-884b-685f85c5cf0a" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019ff6f8-6ee6-7a57-9064-44ad1ec64f3b" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_TradingSymbol_019ff6f8-6ee6-7a57-9064-44ad1ec64f3b" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019ff6f8-6ee6-7f08-b336-60d9cd3132ff" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_SecurityExchangeName_019ff6f8-6ee6-7f08-b336-60d9cd3132ff" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019ff6f8-6ee6-7cc1-a96f-f89ed78f3561" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_EntityEmergingGrowthCompany_019ff6f8-6ee6-7cc1-a96f-f89ed78f3561" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019ff6f8-6ee6-7f08-8991-dc82f90a5ea3" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_EntityCentralIndexKey_019ff6f8-6ee6-7f08-8991-dc82f90a5ea3" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019ff6f8-6ee6-70e5-b76d-713fc74775c9" 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_019ff6f8-6ee6-7583-8333-349d08f0a0bf" xlink:to="loc_dei_AmendmentFlag_019ff6f8-6ee6-70e5-b76d-713fc74775c9" xlink:type="arc" order="21"/>
  </link:definitionLink>
</link:linkbase>
