X0306 4 2019-05-18 0 0001351288 GW PHARMACEUTICALS PLC GWPH 0001754154 Giacobello Scott M. SOVEREIGN HOUSE, VISION PARK, HISTON CAMBRIDGE X0 CB24 9BZ UNITED KINGDOM 0 1 0 0 Chief Financial Officer Ordinary Shares 2019-05-18 4 M 0 8136 0.0013 A 91320 D Ordinary Shares 2019-05-20 4 S 0 4224 14.52 D 87096 D Restricted Stock Units 0.0013 2019-05-18 4 M 0 8136 0.00 D 2019-05-18 2019-05-18 Ordinary Shares 8136 0 D Vesting of restricted stock units previously reported as stock options on the reporting person's Form 3 filed on October 1, 2018. These ordinary shares are subsequently converted into American Depositary Shares ("ADS") of the Issuer. Converted from British Pounds Sterling to U.S. Dollars using currency ratio of 1.00 British Pound Sterling = 1.27 U.S. Dollars as of May 17, 2019. Includes 47,496 and 25,152 ordinary shares underlying restricted stock units previously reported as stock options on the reporting person's Form 3 filed on October 1, 2018 and Form 4 filed on March 5, 2019, respectively. Represented by ADSs. The price reported in Column 4 is price per ordinary share converted from price per ADS. The reporting person's Form 3 filed on October 1, 2018 contained stock options to purchase 8,136 ordinary shares vesting on May 18, 2019 and expiring on March 15, 2020. These securities are restricted stock units with a nominal exercise price and vest automatically upon vesting date. /s/ Scott M. Giaccobello 2019-05-21