William Barnard may refer to:
William Barnard (bishop) (1697–1768), Anglican bishop of Raphoe and Derry William Barnard (engraver) (1774–1849), English mezzotint engraver William O. Barnard (1852–1939), U.S. Representative from Indiana Bill Barnard (1886–1958), New Zealand lawyer and politician William Stebbins Barnard (1849–1887), American biologist