Derek Roy Taunt (16 November 1917 – 15 July 2004) was a British mathematician who worked as a codebreaker during World War II at Bletchley Park. Taunt attended Enfield Grammar, then the City of London School. He studied mathematics at Jesus College, Cambridge between 1936 and 1939. He was accepted as a research student by G. H. Hardy, but this was postponed by the outbreak of World War II. Taunt registered with the Joint Recruiting Board, and was initially allocated to work on ballistics at Kemnal Manor in Chislehurst, preparing range tables for new weapons. Finding that the task required only trivial mathematics ("more like advanced arithmetic than real mathematics"), he sought more appropriate work.