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

    <documentType>3</documentType>
<periodOfReport>2003-10-18</periodOfReport>
    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000821113</issuerCik>
        <issuerName>GEXA CORP</issuerName>
        <issuerTradingSymbol>GEXC</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001268406</rptOwnerCik>
            <rptOwnerName>BURKE JAMES A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>24 GREENWAY PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1846</rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77046</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>1</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle>President and COO</officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeTable>
<nonDerivativeHolding>
<securityTitle>
<value>Common Stock</value>
</securityTitle>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>25000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeHolding>
</nonDerivativeTable>
<derivativeTable>
<derivativeHolding>
<securityTitle>
<value>Employee Stock Option (Right to Buy)</value>
</securityTitle>
<conversionOrExercisePrice>
<value>2.25</value>
</conversionOrExercisePrice>
<exerciseDate>
<footnoteId id="F1"/>
</exerciseDate>
<expirationDate>
<value>2008-10-18</value>
</expirationDate>
<underlyingSecurity>
<underlyingSecurityTitle>
<value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares>
<value>350000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</derivativeHolding>
</derivativeTable>
<footnotes>
<footnote id="F1">This option is 33.4% vested as of October 18, 2003 and an additional 33.3% will vest on October 18, 2004 and on October 18, 2005.</footnote>
</footnotes>
<remarks></remarks>
<ownerSignature>
<signatureName>James A. Burke</signatureName>
<signatureDate>2003-10-29</signatureDate>
</ownerSignature>
</ownershipDocument>

