William Mercer

William Mercer may refer to:
 * William Mercer (poet) (c. 1605–c. 1675), Scottish poet and army officer
 * William Thomas Mercer (1821–1879), British Colonial Secretary in Hong Kong, 1859–1868
 * William W. Mercer, American politician from Montana and former United States Attorney
 * William (Rosko) Mercer (1927–2000), known as Rosko, American news announcer and disc jockey
 * Bill Mercer (born 1926), American sportscaster
 * William Mercer (rugby league) (born 1906), rugby league footballer of the 1930s for England and St Helens RLFC
 * William Mercer (cricketer) (1922–1989), English cricketer
 * William Mercer (Australian politician) (1796–1871), British Army officer, landowner, pastoralist, and politician in colonial New South Wales
 * Willie Mercer (1874–1932), Scottish footballer