X0306 4 2020-07-06 0 0001351288 GW PHARMACEUTICALS PLC GWPH 0001754125 Snyder Douglas B. SOVEREIGN HOUSE, VISION PARK, HISTON CAMBRIDGE X0 CB24 9BZ UNITED KINGDOM 0 1 0 0 Chief Legal Officer Ordinary Shares 2020-07-06 4 S 0 9804 10.50 D 0 D The sale reported was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 5, 2020. Represented by American Depositary Shares of the Issuer ("ADS"). Each ADS represents twelve ordinary shares of the Issuer. The price reported is price per ordinary share converted from price per ADS. Column 5 of Table I of the reporting person's Form 4 filed with the SEC on March 4, 2020 includes 57,492 ordinary shares underlying RSU style share options granted pursuant to the Issuer's Long-Term Incentive Plan, including (i) 19,908 ordinary shares vesting automatically in two equal installments on August 10, 2020 and 2021, (ii) 19,224 ordinary shares vesting automatically in two equal installments on February 26, 2021 and 2022, and (iii) 18,360 ordinary shares vesting automatically in three equal installments on March 1, 2021, 2022, and 2023. These ordinary shares have been excluded from Column 5 of this Form 4 and will be reported as each tranche is vested and automatically exercised. /s/ Douglas B. Snyder 2020-07-08