<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>3</documentType>
<periodOfReport>2003-08-27</periodOfReport>
    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000821113</issuerCik>
        <issuerName>GEXA CORP</issuerName>
        <issuerTradingSymbol>GEXC</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001262013</rptOwnerCik>
            <rptOwnerName>HERRMAN RICK L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TWO RIVERWAY</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1710</rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77056</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector>
<isOfficer>0</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle></officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<derivativeTable>
<derivativeHolding>
<securityTitle>
<value>Common Stock Warrant (Right to Buy)</value>
<footnoteId id="F1"/>
</securityTitle>
<conversionOrExercisePrice>
<value>1.00</value>
</conversionOrExercisePrice>
<exerciseDate>
<value>2003-07-16</value>
</exerciseDate>
<expirationDate>
<value>2010-07-16</value>
</expirationDate>
<underlyingSecurity>
<underlyingSecurityTitle>
<value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares>
<value>458333</value>
</underlyingSecurityShares>
</underlyingSecurity>
<ownershipNature>
<directOrIndirectOwnership>
<value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value>See Footnote</value>
<footnoteId id="F1"/>
</natureOfOwnership>
</ownershipNature>
</derivativeHolding>
</derivativeTable>
<footnotes>
<footnote id="F1">By The Catalyst Fund, Ltd., Southwest/Catalyst Capital, Ltd., and Catalyst-Hall Growth Capital, L.P.  Mr. Herrman is (A) the President and 50% shareholder of RDR Management, Inc., the general partner of The Catalyst Fund, Ltd., (B) the President and 50% shareholder of SWC Management, Inc., the general partner of Southwest/Catalyst Capital, Ltd., and (C) the manager and 33.3% attributive interest holder of Catalyst/Hall Growth Capital Management Company, L.L.C., the general partner of Catalyst-Hall Growth Capital, L.P.  Mr. Herrman disclaims beneficial ownership of the Common Stock Warrant owned by The Catalyst Fund, Ltd., Southwest/Catalyst Capital, Ltd. and Catalyst-Hall Growth Capital, L.P.</footnote>
</footnotes>
<remarks></remarks>
<ownerSignature>
<signatureName>/s/ RICK L. HERRMAN</signatureName>
<signatureDate>2003-09-03</signatureDate>
</ownerSignature>
</ownershipDocument>

