Exhibit 5.1

Execution Version

March 7, 2017

IBERIABANK Corporation

200 West Congress Street

Lafayette, Louisiana 70501

Ladies and Gentlemen:

I am the Executive Vice President, Corporate Secretary and General Counsel of IBERIABANK Corporation, a Louisiana corporation (the “Company”), and in such capacity have acted as counsel for the Company in connection with the sale to the Underwriters (as hereinafter defined) by the Company of 6,100,000 shares of its common stock, par value $1.00 per share (the “Common Stock”), in accordance with the Underwriting Agreement, dated March 1, 2017 (the “Underwriting Agreement”), between the Company and Goldman, Sachs & Co. (“GS”), UBS Securities LLC (“UBS”) and each of the other Underwriters named in Schedule A thereto (collectively, the “Underwriters,” which term shall also include any underwriter substituted as hereinafter provided in Section 11 thereof), for whom GS and UBS are acting as Representatives. All capitalized terms not otherwise defined herein shall have the meanings ascribed to them in the Underwriting Agreement.

In rendering the opinions expressed herein, I, or members of my staff, have examined and relied upon (i) the Registration Statement on Form S-3 (File No. 333-202489) filed by the Company with the Commission on March 4, 2015 (the “Registration Statement”), under the 1933 Act, (ii) the base prospectus, dated March 4, 2015, as supplemented by the preliminary prospectus supplement relating to the Common Stock filed with the Commission on March 1, 2017, pursuant to Rule 424(b) under the 1933 Act and as further supplemented by the final prospectus supplement relating to the Common Stock filed with the Commission on March 3, 2017, pursuant to Rule 424(b) under the 1933 Act, (iii) an executed copy of the Underwriting Agreement, (iv) resolutions (or written consents, as applicable) of the Board of Directors and the Pricing Committee of the Board of Directors of the Company, from meetings held (or actions taken) on February 26, 2017 and March 1, 2017, (v) a copy of the Articles of Incorporation of the Company, as amended or supplemented through the date hereof, (vi) a copy of the Bylaws of the Company, as amended or supplemented through the date hereof, (vii) such other corporate records, certificates and other documents as I have deemed necessary or appropriate for purposes of rendering this letter (viii) the General Disclosure Package and (ix) such records of the Company and such agreements, certificates and receipts of public officials, certificates as to factual matters executed by responsible officers or other representatives of the Company and others, and such other documents as I have deemed necessary or appropriate as a basis for the opinions set forth below.

I have assumed the legal capacity of all natural persons, the genuineness of all signatures; the authenticity, accuracy and completeness of all documents submitted to me as originals; and the conformity to original documents of all documents submitted to me as

facsimile, electronic, certified or photostatic copies, and the authenticity, accuracy and completeness of the originals of such copies. In making my examination of executed documents, I have assumed that the parties thereto, other than the Company, had the power, corporate or other, to enter into and perform all obligations thereunder and have also assumed the due authorization by all requisite action, corporate or other, and the execution and delivery by such parties of such documents and the validity and binding effect thereof on such parties.

Based upon the foregoing and subject to the qualifications, assumptions and limitations stated herein, I am of the opinion that:

I am admitted to practice law in the State of Louisiana and express no opinions as to matters under or involving any laws other than the laws of the State of Louisiana and federal laws of the United States of America.

I hereby consent to the filing of this opinion letter as Exhibit 5.1 to the Company’s Current Report on Form 8-K filed on March 7, 2017 and to the use of my name under the caption “Legal Matters” in the prospectus relating to the Common Stock that is part of the Registration Statement.

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