William, Willie, or Willy Mason may refer to:

• William Mason (poet) (1724–1797), English poet, editor and gardener
• William Mason (architect) (1810–1897), New Zealand architect
• William Mason (composer) (1829–1908), American composer and pianist
• William W. Johnstone (a.k.a. William Mason, 1938–2004), American novelist
• William Mason (director) (fl. 1990s–2010s), director of the Lyric Opera of Chicago
• Willy Mason (born 1984), American singer-songwriter
• William Mason (Downton Abbey), fictional character on the television series Downton Abbey

• William Mason (locomotive builder) (1808–1883), American engineer and builder of locomotives
• William Mason (gunsmith) (1837–1913), American engineer and inventor working for Remington, Colt, and Winchester
• William H. Mason (masonite) (fl. 1920s), American inventor; first patented masonite

• William Temple Thomson Mason (1782–1862), Virginia farmer, businessman and politician
• William Mason (New York politician) (1786–1860), United States Representative from New York
• William S. Mason (1832–1899), American politician; mayor of Portland, Oregon
• William E. Mason (American politician) (1850–1921), U.S. Representative and Senator from Illinois
• William Mason, 1st Baron Blackford (1862–1947), British politician and public servant
• William E. Mason (Canadian politician) (1866–1951), Canadian politician; mayor of Regina, Saskatchewan
• William E. Mason (East St. Louis mayor) (fl. 1970s), American politician; mayor of East Saint Louis, Illinois
• William D. Mason (born 1959), American prosecutor from Cuyahoga County, Ohio

• William Mason (1757–1818), American planter and militiaman in the American Revolutionary War
• William Mason (1760–1830), American Revolutionary War soldier, founder of city of Mason, Ohio
• William Pinckney Mason (1843–1922), American lieutenant in the Confederate States Navy

• William Mason (stenographer) (fl. 1672–1709), English writing-master
• William Mason (religious writer) (1719–1791), English Calvinist author and editor of the Gospel Magazine
• William Shaw Mason (1774–1853), Irish statistician and bibliographer
• William Mason (cricketer) (1811–1865), English cricketer
• Willie Mason (born 1980), Australian rugby league footballer

• William Mason (locomotive), steam locomotive built for the Baltimore and Ohio Railroad

• Bill Mason (disambiguation)

This disambiguation page lists articles associated with the title William Mason.
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