William Hilliard may refer to:
William Hilliard (bishop) (1887–1960), Anglican bishop of Nelson William Hilliard (English MP) (died 1608), English Member of Parliament William Hilliard (Florida politician), served as Mayor of Tallahassee William Hilliard (publisher) (1778–1836), American publisher and bookseller in Massachusetts William A. Hilliard (1927–2017), American journalist William L. Hilliard (1868–1966), Canadian physician and politician in Ontario