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

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2020 Workiva-->
<!--r:24125e80-b22a-4d9a-9bde-bcbefa9abeee,g:c3dd3472-8405-4ecb-94d9-4ccd34977dbc-->
<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://si-bone.com/role/Cover" xlink:type="simple" xlink:href="sibn-20201102.xsd#Cover"/>
  <link:definitionLink xlink:role="http://si-bone.com/role/Cover" xlink:type="extended" id="i03aa9b4247b747edaa1742dde633c589_Cover">
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationLineItems_c5c45112-f532-4bd5-9b97-57d63d1eedff" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_f9753fa1-0215-4ab2-9e2c-093384a22c97" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_c5c45112-f532-4bd5-9b97-57d63d1eedff" xlink:to="loc_dei_DocumentPeriodEndDate_f9753fa1-0215-4ab2-9e2c-093384a22c97" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_3d4b8b9c-d563-4023-93df-251992e485fd" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_c5c45112-f532-4bd5-9b97-57d63d1eedff" xlink:to="loc_dei_DocumentType_3d4b8b9c-d563-4023-93df-251992e485fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_7c7277dd-c351-4677-900b-dea32cf55693" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_c5c45112-f532-4bd5-9b97-57d63d1eedff" xlink:to="loc_dei_EntityAddressPostalZipCode_7c7277dd-c351-4677-900b-dea32cf55693" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_07adfe2e-a911-4066-826c-25f7d750c38a" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_c5c45112-f532-4bd5-9b97-57d63d1eedff" xlink:to="loc_dei_EntityAddressAddressLine1_07adfe2e-a911-4066-826c-25f7d750c38a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine2_4f009e5c-585c-4fa4-930c-778645f650a7" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityAddressAddressLine2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_c5c45112-f532-4bd5-9b97-57d63d1eedff" xlink:to="loc_dei_EntityAddressAddressLine2_4f009e5c-585c-4fa4-930c-778645f650a7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_9a299761-72af-4ca1-832f-7a269962be05" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentInformationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_DocumentInformationLineItems_c5c45112-f532-4bd5-9b97-57d63d1eedff" xlink:to="loc_dei_DocumentInformationTable_9a299761-72af-4ca1-832f-7a269962be05" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
  </link:definitionLink>
</link:linkbase>
