UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of September 2021

Commission File Number 001-15170

GlaxoSmithKline plc

(Translation of registrant's name into English)

980 Great West Road, Brentford, Middlesex, TW8 9GS

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F . . . .X. . . . Form 40-F . . . . . . . .

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ____

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ____

GlaxoSmithKline plc (the 'Company')

Transaction notification

1.	Details of PDMR/person closely associated with them ('PCA')
a)	Name	Sir Jonathan Symonds
b)	Position/status	Non-Executive Chairman
c)	Initial notification/amendment	Initial notification
2.	Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor
a)	Name	GlaxoSmithKline plc
b)	LEI	5493000HZTVUYLO1D793
3.	Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transaction(s) has been conducted
a)	Description of the financial instrument	Ordinary shares of 25 pence each ('Ordinary Shares') ISIN: GB0009252882
b)	Nature of the transaction	Acquisition of notional Ordinary Shares under the share allocation arrangements for Non-Executive Directors for the period of service from 1 July 2021 to 30 September 2021
c)	Price(s) and volume(s)		Price(s)	Volume(s)
			£13.94	3,138.451
d)	Aggregated information	N/A (single transaction)
	Aggregated volume Price
e)	Date of the transaction	2021-09-20
f)	Place of the transaction	N/A

1.	Details of PDMR/person closely associated with them ('PCA')
a)	Name	Mr Charles Bancroft
b)	Position/status	Independent Non-Executive Director
c)	Initial notification/amendment	Initial notification
2.	Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor
a)	Name	GlaxoSmithKline plc
b)	LEI	5493000HZTVUYLO1D793
3.	Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transaction(s) has been conducted
a)	Description of the financial instrument	American Depositary Shares ('ADSs') ISIN: US37733W1053
b)	Nature of the transaction	Acquisition of notional ADSs under the share allocation arrangements for Non-Executive Directors for the period of service from 1 July 2021 to 30 September 2021
c)	Price(s) and volume(s)		Price(s)	Volume(s)
			$39.09	1,479.486
d)	Aggregated information	N/A (single transaction)
	Aggregated volume Price
e)	Date of the transaction	2021-09-20
f)	Place of the transaction	N/A

1.	Details of PDMR/person closely associated with them ('PCA')
a)	Name	Mr Vindi Banga
b)	Position/status	Senior Independent Non-Executive Director
c)	Initial notification/amendment	Initial notification
2.	Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor
a)	Name	GlaxoSmithKline plc
b)	LEI	5493000HZTVUYLO1D793
3.	Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transaction(s) has been conducted
a)	Description of the financial instrument	Ordinary shares of 25 pence each ('Ordinary Shares') ISIN: GB0009252882
b)	Nature of the transaction	Acquisition of notional Ordinary Shares under the share allocation arrangements for Non-Executive Directors for the period of service from 1 July 2021 to 30 September 2021
c)	Price(s) and volume(s)		Price(s)	Volume(s)
			£13.94	650.108
d)	Aggregated information	N/A (single transaction)
	Aggregated volume Price
e)	Date of the transaction	2021-09-20
f)	Place of the transaction	N/A

1.	Details of PDMR/person closely associated with them ('PCA')
a)	Name	Dr Anne Beal
b)	Position/status	Independent Non-Executive Director
c)	Initial notification/amendment	Initial notification
2.	Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor
a)	Name	GlaxoSmithKline plc
b)	LEI	5493000HZTVUYLO1D793
3.	Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transaction(s) has been conducted
a)	Description of the financial instrument	American Depositary Shares ('ADSs') ISIN: US37733W1053
b)	Nature of the transaction	Acquisition of notional ADSs under the share allocation arrangements for Non-Executive Directors for the period of service from 1 July 2021 to 30 September 2021
c)	Price(s) and volume(s)		Price(s)	Volume(s)
			$39.09	200.787
d)	Aggregated information	N/A (single transaction)
	Aggregated volume Price
e)	Date of the transaction	2021-09-20
f)	Place of the transaction	N/A

1.	Details of PDMR/person closely associated with them ('PCA')
a)	Name	Dr Vivienne Cox
b)	Position/status	Independent Non-Executive Director
c)	Initial notification/amendment	Initial notification
2.	Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor
a)	Name	GlaxoSmithKline plc
b)	LEI	5493000HZTVUYLO1D793
3.	Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transaction(s) has been conducted
a)	Description of the financial instrument	Ordinary shares of 25 pence each ('Ordinary Shares') ISIN: GB0009252882
b)	Nature of the transaction	Acquisition of notional Ordinary Shares under the share allocation arrangements for Non-Executive Directors for the period of service from 1 July 2021 to 30 September 2021
c)	Price(s) and volume(s)		Price(s)	Volume(s)
			£13.94	605.273
d)	Aggregated information	N/A (single transaction)
	Aggregated volume Price
e)	Date of the transaction	2021-09-20
f)	Place of the transaction	N/A

1.	Details of PDMR/person closely associated with them ('PCA')
a)	Name	Ms Lynn Elsenhans
b)	Position/status	Independent Non-Executive Director
c)	Initial notification/amendment	Initial notification
2.	Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor
a)	Name	GlaxoSmithKline plc
b)	LEI	5493000HZTVUYLO1D793
3.	Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transaction(s) has been conducted
a)	Description of the financial instrument	American Depositary Shares ('ADSs') ISIN: US37733W1053
b)	Nature of the transaction	Acquisition of notional ADSs under the share allocation arrangements for Non-Executive Directors for the period of service from 1 July 2021 to 30 September 2021
c)	Price(s) and volume(s)		Price(s)	Volume(s)
			$39.09	285.330
d)	Aggregated information	N/A (single transaction)
	Aggregated volume Price
e)	Date of the transaction	2021-09-20
f)	Place of the transaction	N/A

1.	Details of PDMR/person closely associated with them ('PCA')
a)	Name	Dr Laurie Glimcher
b)	Position/status	Independent Non-Executive Director
c)	Initial notification/amendment	Initial notification
2.	Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor
a)	Name	GlaxoSmithKline plc
b)	LEI	5493000HZTVUYLO1D793
3.	Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transaction(s) has been conducted
a)	Description of the financial instrument	American Depositary Shares ('ADSs') ISIN: US37733W1053
b)	Nature of the transaction	Acquisition of notional ADSs under the share allocation arrangements for Non-Executive Directors for the period of service from 1 July 2021 to 30 September 2021
c)	Price(s) and volume(s)		Price(s)	Volume(s)
			$39.09	1,056.776
d)	Aggregated information	N/A (single transaction)
	Aggregated volume Price
e)	Date of the transaction	2021-09-20
f)	Place of the transaction	N/A

1.	Details of PDMR/person closely associated with them ('PCA')
a)	Name	Dr Jesse Goodman
b)	Position/status	Independent Non-Executive Director
c)	Initial notification/amendment	Initial notification
2.	Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor
a)	Name	GlaxoSmithKline plc
b)	LEI	5493000HZTVUYLO1D793
3.	Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transaction(s) has been conducted
a)	Description of the financial instrument	American Depositary Shares ('ADSs') ISIN: US37733W1053
b)	Nature of the transaction	Acquisition of notional ADSs under the share allocation arrangements for Non-Executive Directors for the period of service from 1 July 2021 to 30 September 2021
c)	Price(s) and volume(s)		Price(s)	Volume(s)
			$39.09	348.736
d)	Aggregated information	N/A (single transaction)
	Aggregated volume Price
e)	Date of the transaction	2021-09-20
f)	Place of the transaction	N/A

1.	Details of PDMR/person closely associated with them ('PCA')
a)	Name	Mr Urs Rohner
b)	Position/status	Independent Non-Executive Director
c)	Initial notification/amendment	Initial notification
2.	Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor
a)	Name	GlaxoSmithKline plc
b)	LEI	5493000HZTVUYLO1D793
3.	Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transaction(s) has been conducted
a)	Description of the financial instrument	Ordinary shares of 25 pence each ('Ordinary Shares') ISIN: GB0009252882
b)	Nature of the transaction	Acquisition of notional Ordinary Shares under the share allocation arrangements for Non-Executive Directors for the period of service from 1 July 2021 to 30 September 2021
c)	Price(s) and volume(s)		Price(s)	Volume(s)
			£13.94	605.273
d)	Aggregated information	N/A (single transaction)
	Aggregated volume Price
e)	Date of the transaction	2021-09-20
f)	Place of the transaction	N/A

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: September 22, 2021
	By:/s/ VICTORIA WHYTE --------------------------
	Victoria Whyte
	Authorised Signatory for and on
	behalf of GlaxoSmithKline plc