Sir Simon Lawrance Gass KCMG CVO (born 2 November 1956) is a British civil servant. Since 2019, he has chaired the Joint Intelligence Committee and he also currently serves as the British Prime Minister's representative on Afghanistan. Between 2018 and 2019, he was the Commandant of the Royal College of Defence Studies. During his diplomatic career, he served as British ambassador to Greece and to Iran.