6-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of March 2020

Commission File Number 001-15170

GlaxoSmithKline plc

(Translation of registrant's name into English)

980 Great West Road, Brentford, Middlesex, TW8 9GS

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F . . . .X. . . . Form 40-F . . . . . . . .

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ____

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ____

Issued: 13 March 2020, London UK - LSE Announcement

Publication of Supplementary Prospectus

The following supplementary prospectus dated 13 March 2020 has been approved by the UK Listing Authority and is available for viewing:

GlaxoSmithKline plc, GlaxoSmithKline Capital plc and GSK Capital K.K. £20,000,000,000 Euro Medium Term Note Programme

Copies of the supplementary prospectus and the documents incorporated by reference within it have been submitted to the National Storage Mechanism and will shortly be available for inspection at and can be downloaded from:

www.morningstar.co.uk/uk/NSM

For further information, please contact:

GlaxoSmithKline plc

980 Great West Road

Brentford

Middlesex

TW8 9GS

United Kingdom

Enquiries:

BASIS ON WHICH YOU MAY ACCESS THE SUPPLEMENTARY PROSPECTUS

Please note that the information contained in the supplementary prospectus may be addressed to and/or targeted at persons who are residents of particular countries (specified in the base prospectus) only and is not intended for use and should not be relied upon by any person outside these countries and/or to whom the offer contained in the base prospectus is not addressed. Prior to relying on the information contained in the supplementary prospectus you must ascertain from the base prospectus whether or not you are part of the intended addressees of the information contained therein.

Your right to access this service is conditional upon complying with the above.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorised.