William Percy may refer to:
William de Percy (died c. 1096/9), Anglo-Norman nobleman, crusader and founder of Whitby Abbey William de Percy, 6th Baron Percy (died 1245), English noble William Percy (Sussex MP) (c. 1337–1407), English politician William Percy (bishop) (1428–1462), British bishop William Percy (writer) (1574–1648), English poet and playwright William Percy (portrait artist) (1820–1903), of Manchester, England William Henry Percy (1788–1855), British naval officer William Alexander Percy (politician), (1834–1888) American politician and grandfather of the below William Alexander Percy (1885–1942), American lawyer, planter and poet William Armstrong Percy III (born 1933), American historian and gay activist Lord William Percy (1882–1963), British military officer, barrister, and ornithologist
See also William Percy Carpmael (1864–1936), founder of The Barbarians football club Percy