William Walker may refer to:

• William Walker (composer) (1809–1875), composer in the shape note tradition, author of Southern Harmony
• William Walker (diplomat), U.S. ambassador to El Salvador, 1988–1992; leader of the Kosovo Verification Mission
• William Walker (diver) (1869-1918), the diver who saved Winchester Cathedral from collapse
• William Walker (soldier) (1824–1860), U.S. soldier and filibuster who tried to conquer Central America; briefly ruled Nicaragua
• William Walker (politician), Irish-born state Assemblyman from New York; father of Jimmy Walker (mayor of New York City, 1926–1932)
• William Walker (US actor), African-American film actor (To Kill a Mockingbird).
• William Walker (assistant), assistant to George Eastman
• William Walker (chef) (born 1969)
• William Walker (fictional character), character in S.M. Stirling Island in the Sea of Time series
• William Walker (footballer), Australian Rules football player with Fitzroy Football Club, 1903–1914
• William Walker (missionary) (1808-1896), missionary in Gabon

See also Bill Walker

William Walker | William Walker