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    <periodOfReport>2021-03-22</periodOfReport>

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    <issuer>
        <issuerCik>0001577368</issuerCik>
        <issuerName>QTS Realty Trust, Inc.</issuerName>
        <issuerTradingSymbol>QTS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001007921</rptOwnerCik>
            <rptOwnerName>BARTER JOHN W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O QTS REALTY TRUST, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>12851 FOSTER STREET</rptOwnerStreet2>
            <rptOwnerCity>OVERLAND PARK</rptOwnerCity>
            <rptOwnerState>KS</rptOwnerState>
            <rptOwnerZipCode>66213</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
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            <isDirector>true</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

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        </nonDerivativeTransaction>
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    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Class A units of Operating Partnership</value>
            </securityTitle>
            <conversionOrExercisePrice>
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                <value>2021-03-22</value>
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                    <footnoteId id="F6"/>
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                <transactionAcquiredDisposedCode>
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                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F6"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2761.00</value>
                </underlyingSecurityShares>
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                    <value>5239.00</value>
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        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
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                <value>2021-03-22</value>
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                <transactionPricePerShare>
                    <value>21.00</value>
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                <transactionAcquiredDisposedCode>
                    <value>D</value>
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            <exerciseDate>
                <value>2014-10-15</value>
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            <expirationDate>
                <value>2023-10-15</value>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
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                    <value>8000.00</value>
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                    <value>D</value>
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        </derivativeTransaction>
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            <securityTitle>
                <value>Class A units of Operating Partnership</value>
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                <footnoteId id="F6"/>
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            <transactionDate>
                <value>2021-03-23</value>
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                <transactionFormType>4</transactionFormType>
                <transactionCode>C</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
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                    <value>1239.00</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F6"/>
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                <transactionAcquiredDisposedCode>
                    <value>D</value>
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            <exerciseDate>
                <footnoteId id="F6"/>
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            <expirationDate>
                <footnoteId id="F6"/>
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                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
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                <underlyingSecurityShares>
                    <value>1239.00</value>
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            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4000.00</value>
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        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">8,000 shares of Class A common stock were acquired upon Mr. Barter's exercise of options to purchase shares of Class A common stock, granted on October 15, 2013 under the QTS Realty Trust, Inc. 2013 Equity Compensation Plan. The options vested on October 15, 2014.</footnote>
        <footnote id="F2">2,761 shares of Class A common stock were acquired upon Mr. Barter's redemption of 2,761 Class A units of the Operating Partnership. Class A units are redeemable for cash or, at the operating partnership's election, shares of the Company's Class A common stock on a one-for-one basis, beginning November 1, 2014, which was one year following the beginning of the first full calendar month following the closing of the Company's initial public offering.</footnote>
        <footnote id="F3">This transaction was executed in multiple trades at prices ranging from $63.00 and $63.06, inclusive; the price reported above reflects the weighted average sale price. The reporting person undertakes to provide to QTS Realty Trust, Inc., any security holder of QTS Realty Trust, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this Footnote.</footnote>
        <footnote id="F4">1,239 shares of Class A common stock were acquired upon Mr. Barter's redemption of 1,239 Class A units of the Operating Partnership. Class A units are redeemable for cash or, at the operating partnership's election, shares of the Company's Class A common stock on a one-for-one basis, beginning November 1, 2014, which was one year following the beginning of the first full calendar month following the closing of the Company's initial public offering.</footnote>
        <footnote id="F5">This transaction was executed in multiple trades at prices ranging from $63.00 and $63.025, inclusive; the price reported above reflects the weighted average sale price. The reporting person undertakes to provide to QTS Realty Trust, Inc., any security holder of QTS Realty Trust, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this Footnote.</footnote>
        <footnote id="F6">Class A units are redeemable for cash or, at the operating partnership's election, shares of the Company's Class A common stock on a one-for-one basis, beginning November 1, 2014, which was one year following the beginning of the first full calendar month following the closing of the Company's initial public offering.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Aga Carpenter, as attorney-in-fact for John W. Barter</signatureName>
        <signatureDate>2021-03-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
