William R. Allen may refer to:
William R. Allen (economist) (1924–2021), American economist, professor and author William Allen (Canadian politician) (1919–1985) William Allen (Montana politician) (1871–1953), American politician and businessman William Allen (Utah architect) (1849–1928) William Reginald Allen (English cricketer) (1893–1950) William Rodney Allen, American author and former professor of English William Ross Allen (1869–1942), American politician and lawyer from Virginia