William Reid may refer to:

• William Allan Reid (1865–1952), British Conservative Party Member of Parliament for Derby 1931–1945
• William Earl Reid (1934–2013), politician in British Columbia, Canada
• William Ferguson Reid (born 1925), Virginia physician, politician and civil rights activist
• William Henry Reid (1846–1912), Ontario farmer and political figure
• William Reid (British politician) (1889–1965), United Kingdom Member of Parliament for Glasgow Provan 1955–1964
• William Reid (New York politician) (1827–1906), American manufacturer and politician from New York

• William Reid (basketball) (1893–1955), basketball coach and administrator
• William Reid (rugby league), rugby league footballer of the 1910s for England, and Widnes
• William Reid (South Australia cricketer) (1867–1943), Australian cricketer
• William Reid (Tasmania cricketer) (1882–1950), Tasmania cricketer

• William Reid (British Army officer) (1791–1858), British soldier and Governor of the Bermudas, Windward Islands, and Malta
• William Reid (civil servant) (born 1931), former Parliamentary and Health Service Ombudsman
• William Reid (mining engineer) (1906–1985), Scottish coal expert and co-author of the "Reid Report" on the state of British coal-mining
• William Reid (musician) (born 1958), guitarist with The Jesus and Mary Chain
• William Reid (Scottish businessman) (1842–?), early financier of railroads in Oregon's Willamette Valley
• William Reid (VC) (1921–2001), Scottish World War II war hero
• William Arbuckle Reid (1933–2015), British educator, curriculum theorist, and philosophical disciple of Joseph Schwab
• William Hamilton Reid (died 1826), British poet and hack writer
• William P. Reid (1854–1932), Scottish locomotive engineer
• William Reid (military historian) (1926–2014), Scottish military historian
• William Reid (psychiatrist), American forensic psychiatrist
• William S. Reid (1778–1853), vice president and acting president of Hampden–Sydney College
• William Reid IV, American lawyer
• Gordon Reid (priest) (William Gordon Reid, born 1942), Anglican priest, former Dean of Gibraltar and Vicar General of the Diocese of Europe

• William Reid, a character in Criminal Minds, father of Dr. Spencer Reid

• William Reed (disambiguation)
• William Reade (disambiguation)
• William Rede (disambiguation)
• William Read (disambiguation)
• Billy Reid (disambiguation)
• Willie Reid (disambiguation)