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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2012-07-30</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000785968</issuerCik>
        <issuerName>MILLER ENERGY RESOURCES, INC.</issuerName>
        <issuerTradingSymbol>MILL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001555226</rptOwnerCik>
            <rptOwnerName>RECTOR CATHERINE A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>9721 COGDILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 302</rptOwnerStreet2>
            <rptOwnerCity>KNOXVILLE</rptOwnerCity>
            <rptOwnerState>TN</rptOwnerState>
            <rptOwnerZipCode>37932</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CHIEF ACCOUNTING OFFICER</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <ownerSignature>
        <signatureName>/s/ Catherine A. Rector</signatureName>
        <signatureDate>2012-07-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
