Publication of a Prospectus

Issued: 4 May 2020, London UK - LSE Announcement

Publication of Supplementary Prospectus

The following supplementary prospectus dated 30 April 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 submitted to the UK Listing Authority's NSM submission portal via the Electronic Submission System (ESS). A copy can be viewed at:

https://data.fca.org.uk/#/nsm/nationalstoragemechanism.

For further information, please contact:

GlaxoSmithKline plc

980 Great West Road

Brentford

Middlesex

TW8 9GS

United Kingdom

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.