Dieter Felix Gerhardt (born 1 November 1935) is a former commodore in the South African Navy and commander of the strategic Simon's Town naval dockyard. He was arrested by the FBI in New York in 1983 following information obtained from a Soviet defector. He was convicted of high treason as a Soviet spy in South Africa together with his second wife, Ruth, who had acted as his courier. Both were released prior to the change of government following the 1994 general election.