X0306 4 2019-03-15 0 0001351288 GW PHARMACEUTICALS PLC GWPH 0001754129 Gover Justin D. SOVEREIGN HOUSE, VISION PARK, HISTON CAMBRIDGE X0 CB24 9BZ UNITED KINGDOM 1 1 0 0 Chief Executive Officer Ordinary Shares 2019-03-15 4 M 0 47851 0.0013 A 564960 D Ordinary Shares 2019-03-15 4 D 0 19 13.88 D 564941 D Ordinary Shares 2019-03-15 4 S 0 23400 14.01 D 541541 D Stock Options 0.0013 2019-03-15 4 M 0 17517 0.00 D 2018-01-06 2019-03-15 Ordinary Shares 17517 0 D Stock Options 0.0013 2019-03-15 4 M 0 30334 0.00 D Ordinary Shares 30334 60668 D Exercise of stock options. Following the exercise, 47,832 of these shares were converted into American Depositary Shares ("ADS") of the Issuer. Each ADS represents twelve ordinary shares of the Issuer. Converted from British Pounds Sterling to U.S. Dollars using currency ratio of 1.00 British Pound Sterling = 1.33 U.S. Dollars as of March 15, 2018. Includes (a) 67,320 ordinary shares underlying restricted stock units previously reported as stock options on Table II of the reporting person's Form 3 filed on October 1, 2018, of which 22,440 shares will vest automatically on February 26, 2020, 2021 and 2022, respectively and (b) 68,016 ordinary shares underlying restricted stock units previously reported as stock options on Table II of the reporting person's Form 4 filed on March 5, 2019, of which 17,004 shares will automatically vest on March 1, 2020, 2021, 2022 and 2023, respectively. The price reported in Column 4 is price per ordinary share converted from price per ADS. The reported sales were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on October 16, 2018. The price reported in Column 4 is a weighted average price per ordinary share ($168.09 per ADS). These shares were sold in multiple transactions at prices ranging from $167.59 per ADS (or $13.97 per ordinary share) to $168.54 per ADS (or $14.05 per ordinary share), inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range. The reported transaction related to exercise of stock options to purchase 30,334 shares which vested on February 15, 2018. The remaining stock options vest equally on February 15, 2019 and 2020, and will expire 13 months after vesting date. /s/ Justin D. Gover 2019-03-19