Exhibit 5.1

OPINION OF WILSON SONSINI GOODRICH & ROSATI

PROFESSIONAL CORPORATION

August 29, 2013

Cvent, Inc.

8180 Greensboro Dr.

9^th Floor

McLean, VA 22102

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 Cvent, Inc., a Delaware corporation, 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 3,335,994 shares of the Company’s Common Stock, par value $0.001 per share (“Common Stock”), reserved for issuance pursuant to the Company’s Stock Incentive Plan and 4,945,478 shares of Common Stock reserved for issuance pursuant to the Company’s 2013 Equity Incentive Plan (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 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,

/s/ WILSON SONSINI GOODRICH & ROSATI

WILSON SONSINI GOODRICH & ROSATI

Professional Corporation