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

    <schemaVersion>X0607</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2026-05-06</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001341439</issuerCik>
        <issuerName>ORACLE CORP</issuerName>
        <issuerTradingSymbol>ORCL</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001917584</rptOwnerCik>
            <rptOwnerName>Mihaljevic Tomislav</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O DELPHI ASSET MGMT CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>200 S. VIRGINIA ST., SUITE 625</rptOwnerStreet2>
            <rptOwnerCity>RENO</rptOwnerCity>
            <rptOwnerState>NV</rptOwnerState>
            <rptOwnerZipCode>89501</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <footnotes></footnotes>

    <remarks>Exhibit 24.1 - Power of Attorney</remarks>

    <ownerSignature>
        <signatureName>/s/ Aimee Weast by Aimee Weast, Attorney in Fact for Tomislav Mihaljevic (POA filed 5/14/2026)</signatureName>
        <signatureDate>2026-05-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
