Frank Ezra Adcock (1886 – 1968) was a British classical historian of Greece and Rome, and worked as a cryptographer in both World Wars.
He was born in Desford, Leicestershire, and died at Cambridge. He was educated at King’s College, Cambridge. He became a fellow and lecturer there in 1911, and held the Chair of Ancient History at Cambridge from 1925 to 1951 when he retired. With J. B. Bury and S. A. Cook he edited the Cambridge Ancient History, which was published from 1923 to 1939, and also wrote ten chapters of it.
He was involved in cryptography in Room 40 in World War I, and at Bletchley Park from 1939 to 1943.