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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019d4a7a-ee01-763f-9790-d42ae49fd8fd,g:f5a1b411-e495-4c55-b32d-91dfe74e072c-->
<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.ventasreit.com/role/Cover" xlink:type="simple" xlink:href="vtr-20260427.xsd#Cover"/>
  <link:definitionLink xlink:role="http://www.ventasreit.com/role/Cover" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationLineItems_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_019d4a7a-ee01-7c98-8af8-6b47ce065e96" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_DocumentInformationTable_019d4a7a-ee01-7c98-8af8-6b47ce065e96" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityListingsExchangeAxis_019d4a7a-ee01-777f-a049-24ff06a89660" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityListingsExchangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_019d4a7a-ee01-7c98-8af8-6b47ce065e96" xlink:to="loc_dei_EntityListingsExchangeAxis_019d4a7a-ee01-777f-a049-24ff06a89660" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_019d4a7a-ee01-777f-a049-24ff06a89660_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_EntityListingsExchangeAxis_019d4a7a-ee01-777f-a049-24ff06a89660" xlink:to="loc_dei_ExchangeDomain_019d4a7a-ee01-777f-a049-24ff06a89660_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_019d4a7a-ee01-7f1a-82ba-d03f6fbc312a" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_EntityListingsExchangeAxis_019d4a7a-ee01-777f-a049-24ff06a89660" xlink:to="loc_dei_ExchangeDomain_019d4a7a-ee01-7f1a-82ba-d03f6fbc312a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_exch_XNYS_019d4a7a-ee01-75d5-b778-24f3d4965883" xlink:href="https://xbrl.sec.gov/exch/2026/exch-2026.xsd#exch_XNYS"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_ExchangeDomain_019d4a7a-ee01-7f1a-82ba-d03f6fbc312a" xlink:to="loc_exch_XNYS_019d4a7a-ee01-75d5-b778-24f3d4965883" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019d4a7a-ee01-7911-b2c4-3bfbc939e552" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_DocumentType_019d4a7a-ee01-7911-b2c4-3bfbc939e552" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019d4a7a-ee01-7a08-ab7c-1c3634faf92b" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_DocumentPeriodEndDate_019d4a7a-ee01-7a08-ab7c-1c3634faf92b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019d4a7a-ee01-7c16-b09b-75e655c5d50c" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_EntityRegistrantName_019d4a7a-ee01-7c16-b09b-75e655c5d50c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019d4a7a-ee01-731c-8837-33c9ddb437be" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019d4a7a-ee01-731c-8837-33c9ddb437be" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019d4a7a-ee01-7480-9b6c-c9cd97f232fa" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_EntityFileNumber_019d4a7a-ee01-7480-9b6c-c9cd97f232fa" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019d4a7a-ee01-71f6-991f-9262d89dd288" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_EntityTaxIdentificationNumber_019d4a7a-ee01-71f6-991f-9262d89dd288" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019d4a7a-ee01-70ad-89bf-7704996c28a6" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_EntityAddressAddressLine1_019d4a7a-ee01-70ad-89bf-7704996c28a6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019d4a7a-ee01-714a-b676-a28dbfc740c8" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_EntityAddressCityOrTown_019d4a7a-ee01-714a-b676-a28dbfc740c8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019d4a7a-ee01-79d3-a223-27b951f13476" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_EntityAddressStateOrProvince_019d4a7a-ee01-79d3-a223-27b951f13476" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019d4a7a-ee01-7593-86a3-09a72b19a5e2" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_EntityAddressPostalZipCode_019d4a7a-ee01-7593-86a3-09a72b19a5e2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019d4a7a-ee01-7bfd-8ec6-b1584b816bc3" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_CityAreaCode_019d4a7a-ee01-7bfd-8ec6-b1584b816bc3" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019d4a7a-ee01-7eb9-bc83-7c4d47b24c09" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_LocalPhoneNumber_019d4a7a-ee01-7eb9-bc83-7c4d47b24c09" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_019d4a7a-ee01-785f-b71c-521a77042171" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_WrittenCommunications_019d4a7a-ee01-785f-b71c-521a77042171" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_019d4a7a-ee01-769b-818b-77433f29bd78" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_SolicitingMaterial_019d4a7a-ee01-769b-818b-77433f29bd78" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_019d4a7a-ee01-7695-8f20-0b457e3854ff" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_PreCommencementTenderOffer_019d4a7a-ee01-7695-8f20-0b457e3854ff" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_019d4a7a-ee01-71eb-9ae8-9666776d4430" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_019d4a7a-ee01-71eb-9ae8-9666776d4430" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019d4a7a-ee01-755a-b834-ceb58b4c4d1a" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_Security12bTitle_019d4a7a-ee01-755a-b834-ceb58b4c4d1a" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019d4a7a-ee01-7070-a40f-6f9c682bea64" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_TradingSymbol_019d4a7a-ee01-7070-a40f-6f9c682bea64" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019d4a7a-ee01-7341-a83d-d6df3f48e3fa" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_SecurityExchangeName_019d4a7a-ee01-7341-a83d-d6df3f48e3fa" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019d4a7a-ee01-73f4-91c7-905e68534019" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_EntityCentralIndexKey_019d4a7a-ee01-73f4-91c7-905e68534019" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019d4a7a-ee01-731a-8399-1a0662792c06" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_AmendmentFlag_019d4a7a-ee01-731a-8399-1a0662792c06" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019d4a7a-ee01-7879-91e9-6ab94358ebd6" 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_019d4a7a-ee01-7ebb-b137-d63cd455923c" xlink:to="loc_dei_EntityEmergingGrowthCompany_019d4a7a-ee01-7879-91e9-6ab94358ebd6" xlink:type="arc" order="21"/>
  </link:definitionLink>
</link:linkbase>