William Arthur may refer to:
- William Arthur (botanist) (fl. 1715), Scottish botanist
- William Arthur (clergyman) (1796–1875), Irish-born American Baptist minister and father of President Chester A. Arthur
- William Arthur (minister) (1819–1901), Wesleyan Methodist minister and author
- William Arthur (mathematician) (1894–1979), British mathematician
- William Brian Arthur (born 1945), a.k.a. W. Brian Arthur, Irish economist
- William Evans Arthur (1825–1897), U.S. politician
- William Arthur (Royal Navy) (1830–1886), British naval officer
- William Hemple Arthur (1856–1936), American general and doctor
- Bill Arthur (1918–1982), Australian politician