Tremayne is a Cornish language surname.

Notable people with the surname include:

• Arthur Tremayne (1827–1905), Crimean War soldier and Cornish MP
• David Tremayne, British motorcycling journalist
• Edmund Tremayne (c. 1525 – 1582), English conspirator and official dedicated to Protestantism in opposition to Mary I of England
• Henry Hawkins Tremayne (1741–1829), clergyman and squire of Heligan
• John Hearle Tremayne (1780–1851), Cornish MP and High Sheriff of Cornwall
• John Tremayne (1825–1901), MP for constituencies in both Cornwall and Devon, and High Sheriff of Cornwall
• John Tremayne Babington (later John Tremayne Tremayne), British Air Marshal and High Sheriff of Cornwall
• Les Tremayne (1913–2003), English radio, film, and television actor

Notable people with the given name include:

• Tremayne Anchrum (born 1998), American football player