He was educated at Farnborough Prep school and Eton before going up to Oxford. Old Etonian Arthur Balfour recommended the Debating Society to him. His father was also friendly with Frances Horner, wife of Sir John Horner, a longtime friend of Gladstone who lived at Mells Manor in Somerset. His house master was a member of the secret society of liberals, the Young Apostles. Also a near contemporary was Osbert Sitwell, the Yorkshireman and author. A French scholar, he learned the language doing classes at Windsor Castle. Sassoon was taught aesthetics by Henry Luxmoore giving an insight into philosophy and social realism. However he chose to read Modern History at Christ Church, Oxford. He was one of only 25 Jewish undergraduates, but was invited to join the Bullingdon Club. He joined the East Kent Yeomanry while still at Oxford and was commissioned as a second lieutenant.