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 11, 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

The Administrators of the GlaxoSmithKline Executive Supplemental Savings Plan
notified the Company and the under-mentioned persons on 11 April 2008 of changes
in their interests in Ordinary share ADRs arising from an increase in their
interests under the Annual Investment Plan feature following the re-investment
of the dividend paid to shareholders on 10 April 2008 at a price of $43.84 per

Dr J P Garnier                                            596.14
Dr D Pulman                                                32.12

This notification relates to a transaction notified in accordance with
Disclosure and Transparency Rule 3.1.4R(1)(a).

S M Bicknell
Company Secretary

11 April 2008


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

Date: April 11, 2008                                      By: VICTORIA WHYTE
                                                              Victoria Whyte
                                                 Authorised Signatory for and on
                                                   behalf of GlaxoSmithKline plc