William Martyn

William Martyn may refer to:


 * William Martyn (Lord Mayor) (c. 1446–1503), Sheriff of London and Lord Mayor of London
 * William Óge Martyn (died 1592), mayor of Galway
 * William Martyn (historian) (1562–1617), English lawyer and historian
 * Will Martyn (born 2001), Australian rules footballer