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    <periodOfReport>2026-01-02</periodOfReport>

    <issuer>
        <issuerCik>0001677576</issuerCik>
        <issuerName>INNOVATIVE INDUSTRIAL PROPERTIES INC</issuerName>
        <issuerTradingSymbol>IIPR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001689305</rptOwnerCik>
            <rptOwnerName>Shoemaker Scott</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O INNOVATIVE INDUSTRIAL PROPERTIES</rptOwnerStreet1>
            <rptOwnerStreet2>11440 WEST BERNARDO COURT, SUITE 100</rptOwnerStreet2>
            <rptOwnerCity>SAN DIEGO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92127</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

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        <derivativeHolding>
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                <underlyingSecurityTitle>
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                    <value>1249</value>
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                </natureOfOwnership>
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        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
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                <value>0</value>
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                <underlyingSecurityTitle>
                    <value>Common Stock</value>
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                <underlyingSecurityShares>
                    <value>883</value>
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                    <value>883</value>
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    <footnotes>
        <footnote id="F1">Each restricted stock unit (&quot;RSU&quot;) represents the contingent right to receive, upon vesting of the RSU, one share of Innovative Industrial Properties, Inc. (the &quot;Company&quot;) common stock.</footnote>
        <footnote id="F2">The vesting of RSUs is subject to the satisfaction of the vesting conditions under the Company's NQDC Plan.</footnote>
        <footnote id="F3">All of the RSUs shall be released from the forfeiture restriction on June 11, 2026, provided that the reporting person continues to be a non-employee director or employee of the Company on such date. The vesting of RSUs is subject to satisfaction of the vesting conditions under the Company's Nonqualified Deferred Compensation Plan (the &quot;NQDC Plan&quot;</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Scott Shoemaker</signatureName>
        <signatureDate>2026-02-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
