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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-10-19</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001348334</issuerCik>
        <issuerName>BARRACUDA NETWORKS INC</issuerName>
        <issuerTradingSymbol>CUDA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001590742</rptOwnerCik>
            <rptOwnerName>Golob David R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O FRANCISCO PARTNERS MANAGEMENT, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>ONE LETTERMAN DRIVE, BUILDING C- STE 410</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94129</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-10-19</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1999147</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4154465</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-10-19</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>83209</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                    <footnoteId id="F2"/>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4237674</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On October 19, 2016, each of Francisco Partners, L.P. (&quot;LP I&quot;), Francisco Partners Fund A, L.P. (&quot;FPFA&quot;), Francisco Partners Fund III, L.P. (&quot;FP III&quot;) and Francisco Partners Parallel Fund III, L.P. (&quot;FPPF III&quot;) made pro rata distributions of common stock of Barracuda Networks, Inc., par value $0.001 per share (&quot;Common Stock&quot;), without any additional consideration, to their respective limited and general partners.</footnote>
        <footnote id="F2">In connection with the transactions described in footnote 1 herein, (i) FPFA's pro rata distribution of Common Stock included the disposition of Common Stock to Francisco Partners GP, LLC (&quot;FP GP LLC&quot;), and (ii) FP III's pro rata distribution of Common Stock included the disposition of Common Stock to Francisco Partners GP III, L.P. (&quot;FP GP III LP&quot;).</footnote>
        <footnote id="F3">These securities include Common Stock directly held and beneficially owned by Francisco Partners (as defined herein) as well as the 4,753 shares of Common Stock either directly held or beneficially owned, through one or more family trusts, by Mr. Golob.</footnote>
        <footnote id="F4">The general partner of each of FP I and FPFA is FP GP LLC. The general partner of each of FP III and FPPF III is FP GP III LP. The general partner of FP GP III LP is Francisco Partners GP III Management, LLC (&quot;FP GP III Mgmt&quot;, and collectively with FP I, FPFA, FP III, FPPF III, FP GP LLC and FP GP III LP, &quot;Francisco Partners&quot;).</footnote>
        <footnote id="F5">Mr. Golob, an officer of an affiliate of Francisco Partners, is a member of the board of directors of the Issuer. Each of FP I, FPFA, FP III, FPPF III, FP GP LLC, FP GP III LP and FP GP III Mgmt are affiliates of Francisco Partners and have each filed separate Form 4s reporting transactions in Common Stock that each may be deemed to beneficially own. Mr. Golob disclaims beneficial ownership of any Common Stock of the Issuer that may be deemed to be beneficially owned by affiliates of Francisco Partners, including each of FP I, FPFA, FP III, FPPF III, FP GP LLC, FP GP III LP and FP GP III Mgmt, except to the extent of his pecuniary interest therein.</footnote>
    </footnotes>

    <remarks>This report is one of three reports, each on a separate Form 4, but relating to the same transaction being filed by Francisco Partners and certain of its affiliated funds and partners. Prior to the transactions described herein, the Reporting Person may be deemed to be, but does not concede to being, a member of a group holding over 10% of the outstanding common stock of the Issuer for purposes of Section 13(d)(3) of the Securities Exchange Act of 1934.</remarks>

    <ownerSignature>
        <signatureName>By: /s/ David R. Golob</signatureName>
        <signatureDate>2016-10-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
