William Mason may refer to:
- William Mason (Colt), American machinist and inventor working for Samuel Colt
- William Mason (composer) (1829–1908), American composer and pianist
- William Mason (locomotive builder) (1808–1883)
- William Mason (architect) (1810-1897), architect & first mayor of Dunedin, New Zealand
- William Mason (poet) (1724–1797), English poet, editor and gardener
- William Mason (religious writer) (1719–1791), Calvinist author and editor of the Gospel Magazine
- William Mason (US politician) (1786-1860), United States Representative from New York
- William D. Mason, prosecutor from Cuyahoga County, Ohio
- William E. Mason (1850-1921), U.S. Representative and Senator from Illinois
- William E. Mason (mayor) (1866–1951), former mayor of Regina, Saskatchewan, Canada
- William H. Mason, inventor of masonite
- William Todd Mason (usually known as Todd Mason) (b. 1963), American entrepreneur
- Bill Mason (1929–1988), Canadian canoeist and author
- William Mason, a student of Harry Harlow
- William Mason, a pseudonym of William W. Johnstone
- William Mason (1757–1818) (1757–1818), American militiaman in the American Revolutionary War and a prominent Virginia planter
- Willie Mason, Australian rugby league footballer
- Willy Mason, singer-songwriter
- William Mason, 1st Baron Blackford (1862-1947), British politician and public servant
See also
- Bill Mason (disambiguation)
- Billy Mason, American drummer