Tremayne is a Cornish language surname. Notable people with the surname include:
Arthur Tremayne (1827–1905), Crimean War soldier and Cornish MPDavid Tremayne, British motorcycling journalistJohn Claude Lewis Tremayne (1869–1949), last squire of Heligan and better known as "Jack"John Hearle Tremayne (1780–1851), Cornish MP and High Sheriff of Cornwall in 1831John Tremayne (of Collacombe), High Sheriff of Cornwall in 1485John Tremayne (of Tremayne), High Sheriff of Cornwall in 1487John Tremayne (of Heligan), High Sheriff of Cornwall in 1745John Tremayne (1825–1901), MP for constituencies in both Cornwall and Devon, and High Sheriff of Cornwall in 1859Henry Hawkins Tremayne (1741–1829), clergyman and squire of HeliganKate Tremayne, British novelistPeter Tremayne, pseudonym of Peter Berresford Ellis (b. 1943) British biographer, historian, and novelistDick Tremayne, character in Twin PeaksTremayne, (Anthony Nicholls), a character in The Champions, a British TV series on the UK network ITV during 1968–69John Tremayne Babington (later John Tremayne Tremayne), British Air Marshal and High Sheriff of Cornwall in 1954Jorge Tremayne, U.S. Navy 1973–1984