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 May 20, 208

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

Following a re-valuation of the cash element of the notional investment held within the US Retirement Savings Plan (“The Plan”), which is notionally held in GSK Ordinary Share ADRs, the Administrators of the Plan notified GlaxoSmithKline plc and the under-mentioned person on 19 May 2008 of an increase in the notional allocation of Ordinary Share ADRs on 16 May 2008 at a price of $44.46 per ADR:-

Dr R G Greig

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

S M Bicknell
Company Secretary








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: May 20, 2008                                                                                                              By: VICTORIA WHYTE
                                                              Victoria Whyte
                                                 Authorised Signatory for and on
                                                   behalf of GlaxoSmithKline plc