Exhibit 5.1

OPINION OF WILSON SONSINI GOODRICH & ROSATI,

PROFESSIONAL CORPORATION

May 10, 2012

WageWorks, Inc.

1100 Park Place, 4th Floor

San Mateo, California 94403

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 WageWorks, Inc., a Delaware corporation, with the Securities and Exchange Commission on or about the date hereof, in connection with the registration under the Securities Act of 1933, as amended, of an aggregate of 6,029,556 shares of your common stock, par value $0.001 per share (the “Shares”), reserved for issuance pursuant to the Amended and Restated 2010 Equity Incentive Plan, the 2012 Employee Stock Purchase Plan and the 2000 Stock Option/Stock Issuance Plan (the “Plans”). As your legal counsel, we have reviewed the actions proposed to be taken by you in connection with the issuance and sale of the Shares to be issued under the Plans.

It is our 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, P.C.

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