GlaxoSmithKline plc

(the "Company")

Notification of Transactions of Directors, Persons Discharging Managerial Responsibilities or Connected Persons

In accordance with DTR 3.1.4 R (1) (a), I give details of changes in the interests in the Company's Ordinary Shares of 25p each ("Ordinary Shares") for Ms Claire Thomas, a Person Discharging Managerial Responsibilities, following the sale of 30,000 Ordinary Shares on 3 May 2016 at a price of £14.59 per Ordinary Share.

The Company and Ms Thomas were advised of this transaction on 3 May 2016.

V A Whyte

Company Secretary

3 May 2016