Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in this Registration Statement of ConnectOne Bancorp, Inc. on Amendment No. 2 to Form S-4 of our report dated March 13, 2015 on the consolidated financial statements and effectiveness of internal control over financial reporting appearing in the 2014 Form 10-K of ConnectOne Bancorp, Inc. and to the reference to us under the heading “Experts” in the prospectus.

/s/ Crowe Horwath LLP

Crowe Horwath LLP

Livingston, New Jersey

November 12, 2015