William Brett may refer to: William Brett, 1st Viscount Esher (1815–1899), British lawyer and politician William Henry Brett (missionary) (1818–1886), Anglican missionary to British Guiana William Howard Brett (1846–1918), American librarian William H. Brett (1893–1989), American civil servant William Henry Brett (British Columbia politician) (1895–1972), Canadian politician in British Columbia William Brett, Baron Brett (1942–2012), British politician