William Brett

William Brett may refer to:
 * William Brett, 1st Viscount Esher (1815–1899), British 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