Field Marshal Sir Archibald James Halkett Cassels, GCB, KBE, DSO (28 February 1907 – 13 December 1996) was a senior British Army officer who served as Chief of the General Staff (CGS), the professional head of the British Army, from 1965 to 1968. As a young man he was a first-class cricket player, initially playing in India for the Europeans against the Hindus in the Lahore Tournament and going on to play for a Punjab Governor's XI against Northern India team and for a Viceroy's XI against the Roshanara Club. He later played for the British Army cricket team against the RAF at The Oval and then played for the Egyptian national side against HM Martineau's XI in Alexandria.