Exhibit 5.1 Wilson Sonsini Goodrich & RosatiProfessional Corporation 650 Page Mill Road, Palo Alto, California 94304-1050 o: 650.493.9300 f: 650.493.6811

March 22, 2021

Medallia, Inc.

575 Market Street, Suite 1850

San Francisco, California 94105

Re: Registration Statement on Form S-8

Ladies and Gentlemen:

We have examined the Registration Statement on Form S-8 (the “Registration Statement”) to be filed by Medallia, Inc., a Delaware corporation (the “Company”), with the Securities and Exchange Commission on or about the date hereof, relating to the registration under the Securities Act of 1933, as amended, of (i) 7,749,790 shares of common stock, par value $0.001 per share (“Common Stock”), reserved for issuance pursuant to the Company’s 2019 Equity Incentive Plan and (ii) 1,548,958 shares of Common Stock reserved for issuance pursuant to the Company’s 2019 Employee Stock Purchase Plan, as amended (which plans are referred to herein as the “Plans” and which shares of Common Stock are referred to herein as the “Shares”).

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when issued and sold in the manner referred to in the Plans and pursuant to the agreements that accompany the Plans, will be legally and validly issued, fully paid, and nonassessable.

We consent to the use of this opinion as an exhibit to the Registration Statement and further consent to the use of our name wherever appearing in the Registration Statement and any amendments thereto.

    Very truly yours,

    WILSON SONSINI GOODRICH & ROSATI

    Professional Corporation

    /s/ Wilson Sonsini Goodrich & Rosati, P.C.

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