Exhibit 5.1

Teekay LNG Partners L.P.
4th Floor, Belvedere Building
69 Pitts Bay Road
Hamilton HM 08
Bermuda
Our reference: 25246.50108/80444458v2
May 15, 2020
Registration Statement on FormF-3 – Exhibit 5.1 Opinion
Ladies and Gentlemen:
We have acted as special counsel as to matters of the law of the Republic of the Marshall Islands (“Marshall Islands Law”) for Teekay LNG Partners L.P., a Marshall Islands limited partnership (the “Partnership”), in connection with the preparation and filing with the Securities and Exchange Commission, pursuant to the Securities Act of 1933, as amended (the “Securities Act”), and the rules and regulations promulgated thereunder (the “Rules”), of a registration statement onForm F-3 filed with the U.S. Securities and Exchange Commission on the date hereof (together with any amendments, including any post-effective amendments, the “Registration Statement”), and a prospectus included therein (the “Prospectus”) for the registration of the resale, from time to time, by Teekay GP L.L.C., a Marshall Islands limited liability company and the general partner of the Partnership (the “GeneralPartner”), of up to 10,750,000 common units representing limited partnership interests in the Partnership (the “ResaleUnits”) which were issued pursuant to an Exchange Agreement entered into between the Partnership and the General Partner, dated as of May 9, 2020 (the “Exchange Agreement”).
As such counsel, we have examined originals or copies (certified or otherwise identified to our satisfaction) of all such documents, including (i) the Registration Statement, (ii) the Prospectus, (iii) the certificate of limited partnership and Fifth Amended and Restated Limited Partnership of the Partnership, each as amended to date, (iv) the Exchange Agreement, and (v) such other records, certificates, agreements, documents or other instruments, and such certificates or comparable documents of public officials and of officers and representatives of the Partnership as we have deemed relevant and necessary.
In such examination, we have assumed: (a) the legal capacity of each natural person, (b) the genuineness of all signatures and the authenticity of all documents submitted to us as originals, (c) the conformity to original documents of all documents submitted to us as conformed or photostatic copies, (d) that the documents reviewed by us in connection with the rendering of the opinion set forth herein are true, correct, and complete, and (e) the truthfulness of each statement as to all factual matters contained in any document or certificate encompassed within the due diligence review undertaken by us. We have further assumed the validity and enforceability of all documents under all applicable laws other than Marshall Islands Law. We have further assumed the validity and enforceability of the Exchange Agreement under all applicable laws other than Marshall Islands Law.
As to any questions of fact material to our opinion, we have, when relevant facts were not independently established, relied upon the aforesaid certificates or comparable documents. We have not independently verified the facts so relied on.

Watson Farley & Williams LLP is a limited liability partnership that (for a WFW Affiliated Entity) has an office in each of the cities listed above.