Sir (Philip) Stuart Milner-Barry KCVO, CB, OBE (20 September 1906 – 25 March 1995) was a British chess player, chess writer, World War II codebreaker and civil servant. He represented England in chess both before and after World War II. He worked at Bletchley Park during World War II, and was head of "Hut 6", a section responsible for deciphering messages which had been encrypted using the German Enigma machine.