<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2021-06-09</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000007039</issuerCik>
        <issuerName>TRECORA RESOURCES</issuerName>
        <issuerTradingSymbol>TREC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001804502</rptOwnerCik>
            <rptOwnerName>Ortelius Advisors, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>450 PARK AVENUE, SUITE 2700</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001645708</rptOwnerCik>
            <rptOwnerName>Pangaea Ventures, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ORTELIUS ADVISORS, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>450 PARK AVENUE, SUITE 2700</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001863646</rptOwnerCik>
            <rptOwnerName>Temnein Ventures III, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ORTELIUS ADVISORS, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>450 PARK AVENUE, SUITE 2700</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001804470</rptOwnerCik>
            <rptOwnerName>Desorcy Peter</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>450 PARK AVENUE, SUITE 2700</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2328024</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>163868</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These shares are beneficially owned by Pangaea Ventures, L.P. (&quot;Pangaea&quot;).</footnote>
        <footnote id="F2">These shares are beneficially owned by Temnein Ventures III, L.P. (&quot;Temnein&quot;).</footnote>
        <footnote id="F3">Ortelius Advisors, L.P. (the &quot;Adviser&quot;) is the investment manager of Pangaea and Temnein. Peter DeSorcy is the Managing Member of the general partner of the Adviser, which is the Managing Member of the Adviser, and Mr. DeSorcy has a controlling interest in the Adviser. The Adviser and Mr. DeSorcy disclaim beneficial ownership of any of the shares of common stock owned by Pangaea and Temnein, except to the extent of their pecuniary interest therein.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>ORTELIUS ADVISORS, L.P. By: Ortelius Management, LLC, its general partner By: /s/ Peter DeSorcy Name: Peter DeSorcy Title: Managing Member</signatureName>
        <signatureDate>2021-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>PANGAEA VENTURES, L.P. By: Ortelius Advisors GP I, LLC, its general partner By: /s/ Peter DeSorcy Name: Peter DeSorcy Title: Managing Member</signatureName>
        <signatureDate>2021-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>TEMNEIN VENTURES III, L.P. By: Temnein Advisors GP III, LLC, its general partner By: /s/ Peter DeSorcy Name: Peter DeSorcyTitle: Managing Member</signatureName>
        <signatureDate>2021-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Peter DeSorcy</signatureName>
        <signatureDate>2021-06-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
