SECURITIES AND EXCHANGE COMMISSION Washington D.C. 20549 Report of Foreign Issuer Pursuant to Rule 13a-16 or 15d-16 of the Securities Exchange Act of 1934 For period ending April 02, 2008 GlaxoSmithKline plc (Name of registrant) 980 Great West Road, Brentford, Middlesex, TW8 9GS (Address of principal executive offices) Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F Form 20-F x Form 40-F -- Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934. Yes No x -- Notification of Transactions of Directors, Persons Discharging Managerial Responsibility or Connected Persons I give below details of changes in the directors' interests in the Ordinary shares and American Depository Shares (ADSs) of GlaxoSmithKline plc. On 31 March 2008, the Company's Non-Executive Directors were provisionally allocated the following awards over Ordinary Shares and ADSs under the share allocation arrangements for Non-Executive Directors for the period of service from 1 January 2008 to 31 March 2008: Non Executive Director Ordinary Shares American Depository Shares (ADSs) Sir Christopher Gent 2,694.47 Prof Sir Roy Anderson 761.48 Dr Stephanie Burns 321.03 Mr Lawrence Culp 642.07 Sir Crispin Davis 2,343.02 Sir Deryck Maughan 642.07 Dr Daniel Podolsky 481.55 Sir Ian Prosser 1522.96 Dr Ronaldo Schmitz 937.21 Mr Tom de Swaan 761.48 Sir Robert Wilson 702.91 The Company and the Non-Executive Directors were informed of these allocations on 1 April 2008. This notification relates to transactions notified in accordance with Disclosure and Transparency Rule 3.1.4R(1)(a). S M Bicknell Company Secretary 2 April 2008 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. GlaxoSmithKline plc (Registrant) Date: April 02, 2008 By: VICTORIA WHYTE ------------------ Victoria Whyte Authorised Signatory for and on behalf of GlaxoSmithKline plc