William Rees
William Rees may refer to:
Sports
- William Rees (rugby), rugby union and rugby league footballer of the 1920s and 1930s
- William Lee Rees, English-born New Zealand cricketer, politician and lawyer
- Billy Rees, association footballer of the 1940s and 1950s
Religious figures
- William Rees (priest and writer), earlier Welsh Anglican priest
- William Jenkins Rees, Welsh cleric and antiquary
- William Rees (archdeacon of St Asaph), later Welsh Anglican priest
Others
- William Rees (Liberal politician), in 1390 MP for Norfolk
- William Hurst Rees, British surveyor and member of the Lands Tribunal
- William James Rees, British hydroid and cephalopod researcher
- William E. Rees, originator of "ecological footprint" concept
- William Rees (cinematographer), American cinematographer
- William Rees (Gwilym Hiraethog), writer
- William Rees (veterinary surgeon), Chief Veterinary Officer of the United Kingdom, 1980–1988
- William Gilbert Rees, explorer, surveyor, and early settler in Central Otago, New Zealand