Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in this Registration Statement on Form S-8 of our reports dated February 22, 2012, relating to the consolidated financial statements of ACI Worldwide, Inc. and subsidiaries (the “Company”) and the effectiveness of the Company’s internal control over financial reporting, appearing in the Annual Report on Form 10-K of ACI Worldwide, Inc. for the year ended December 31, 2011.

/s/ Deloitte & Touche LLP

Omaha, Nebraska

July 6, 2012