Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We have issued our reports dated February 24, 2017, with respect to the consolidated financial statements, schedule and internal control over financial reporting included in the Annual Report on Form 10-K for the year ended December 31, 2016 of Qualys, Inc., which is incorporated by reference in this Registration Statement. We consent to the incorporation by reference of the aforementioned reports in the Registration Statement.