EXHIBIT 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the following Registration Statements of First Financial Bancorp:

Form S-8 No.  338-86781

Form S-3 No.  333-25745

Form S-3 No.  333-156841

Form S-3 No.  333-153751

Form S-8 No.  333-168675

Form S-8 No.  333-188593

Form S-3 No. 333-197771

Form S-8 No. 333-218188

Form S-3 No. 333-219554

Form S-4 No. 333-220583

of our report dated February 26, 2018, relating to the 2017 consolidated financial statements and effectiveness of internal control over financial reporting, appearing in this Annual Report on Form 10-K.

Crowe Horwath LLP

Indianapolis, Indiana

February 26, 2018