Exhibit 5.1
![LOGO](https://capedge.com/proxy/6-K/0001193125-20-261165/g93705page01.jpg)
October 1, 2020
GlaxoSmithKline plc
980 Great West Road
Brentford, Middlesex TW8 9GS
England
GlaxoSmithKline Capital plc
980 Great West Road
Brentford, Middlesex TW8 9GS
England
Ladies and Gentlemen:
We have acted as special United States counsel to GlaxoSmithKline Capital plc, a public limited company incorporated in England and Wales (“GSK Capital”) and GlaxoSmithKline plc, a public limited company incorporated in England and Wales (“GSK plc”), in connection with the offering pursuant to a registration statement on Form F-3 (Nos. 333-223982 and 333-223982-02), as amended as of its most recent effective date (September 28, 2020), insofar as it relates to the Securities (as defined below) (as determined for purposes of Rule 430B(f)(2) under the Securities Act of 1933, as amended (the “Securities Act”)) (as so amended, including the documents incorporated by reference therein, but excluding Exhibits 25.1, 25.2 and 25.3, the “Registration Statement”) and the prospectus, dated March 28, 2018, as supplemented by the prospectus supplement thereto, dated September 28, 2020 (together, including the documents incorporated by reference therein, the “Prospectus”) of (i) guaranteed debt securities of GSK Capital consisting of U.S.$1,250,000,000 aggregate principal amount of 0.534% Notes due 2023 (the “Debt Securities”) and (ii) the guarantee of GSK plc in respect of the Debt Securities (the “Guarantee” and, together with the Debt Securities, the “Securities”).
The Debt Securities and the related Guarantee were issued under an indenture dated as of April 6, 2004, as supplemented by the First Supplemental Indenture dated as of March 21, 2014, and as further amended and supplemented by the Second Supplemental Indenture dated as of May 15, 2018, among GSK Capital, as issuer, GSK plc, as guarantor, and the Trustee (as successor to Law Debenture Trust Company of New York, pursuant to an Instrument of Resignation, Appointment and Acceptance dated April 12, 2017, among GSK Capital, the Trustee, and Law Debenture Trust Company of New York) (the “Indenture”).
Cleary Gottlieb Steen & Hamilton LLP is a Limited Liability Partnership registered in England and Wales Number 0C310280. It is authorised and regulated
by the Solicitors Regulation Authority. A list of the members and their professional qualifications is open to inspection at the registered office,
2 London Wall Place, London EC2Y 5AU. Clearly Gottlieb Steen & Hamilton LLP or an affiliated entity has an office in each of the cities listed above.