GlaxoSmithKline plc

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

In accordance with DTR 3.1.4R (1) (a) I give details of changes in the interests of Emma Walmsley, a Person Discharging Managerial Responsibilities, in the Ordinary Shares of GlaxoSmithKline plc (the "Company") following the exercise of nil cost options over 14,789 and 5,583 Ordinary Shares on 29 April 2016, granted on 28 February 2013, which vested on 28 February 2016 under the GlaxoSmithKline Deferred Annual Bonus Plan. The Company delivered the net of tax value in shares being 10,605. The fair market value of an Ordinary Share at the points of exercise on 29 April 2016 was £14.78 and £14.79 respectively.

The Company and Emma Walmsley were advised of these transactions on 3 May 2016.

V A Whyte

Company Secretary

3 May 2016