Exhibit 5.1

John T. McKenna

(650) 843-5059

jmckenna@cooley.com

July 19, 2017

Apollo Endosurgery, Inc.

1120 S. Capital of Texas Highway

Building 1, Suite #300

Austin, Texas 78746

Ladies and Gentlemen:

We have acted as counsel to Apollo Endosurgery, Inc., a Delaware corporation, (the “Company”), in connection with the filing of a registration statement on Form S-1 (the “Registration Statement”) with the Securities and Exchange Commission pursuant to Rule 462(b) of Regulation C promulgated under the Securities Act of 1933, as amended, relating to an aggregate of 6,542,453 shares of common stock, par value $0.001 (the “Shares”), including up to 853,363 shares that may be sold pursuant to the exercise of an option to purchase additional shares. The Registration Statement incorporates by reference the Registration Statement on Form S-1 (No. 333-218741), which was declared effective on July 19, 2017 (the “Prior Registration Statement”), including the prospectus which forms a part of the Prior Registration Statement (the “Prospectus”). The Shares are to be sold by the Company as described in the Registration Statement and the Prospectus.

In connection with this opinion, we have examined and relied upon (a) the Registration Statement, the Prior Registration Statement and the Prospectus, (b) the Company’s Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws, each as currently in effect, and (c) the originals or copies certified to our satisfaction of such other documents, records, certificates, memoranda and other instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below. We have undertaken no independent verification with respect to such matters. We have assumed the genuineness and authenticity of all documents submitted to us as originals, and the conformity to originals of all documents submitted to us as copies and the due execution and delivery of all documents where due execution and delivery are a prerequisite to the effectiveness thereof.  As to certain factual matters, we have relied upon a certificate of an officer of the Company and have not sought independently to verify such matters.

Our opinion is expressed only with respect to the General Corporation Law of the State of Delaware.  We express no opinion as to whether the laws of any particular jurisdiction apply and no opinion to the extent that the laws of any jurisdiction other than those identified above are applicable to the subject matter hereof.  We are not rendering any opinion as to compliance with any federal or state law, rule or regulation relating to securities, or to the sale or issuance thereof.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when sold and issued against payment therefore in accordance with the Registration Statement and the Prospectus, will be validly issued, fully paid and nonassessable.

3175 HANOVER STREET, PALO ALTO, CA 94304-1130  T: (650) 843-5000  F: (650) 849-7400  WWW.COOLEY.COM

We consent to the reference to our firm under the caption “Legal Matters” in the Prospectus included in the Registration Statement and to the filing of this opinion as an exhibit to the Registration Statement. This opinion is expressed as of the date hereof, and we disclaim any undertaking to advise you of any subsequent changes in the facts stated or assumed herein or of any subsequent changes in applicable law.

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