William Cain

William Cain may refer to:


 * William Cain (American politician) (1792–1878), lieutenant governor of South Carolina
 * William Cain (Australian politician), Mayor of Melbourne, Australia (1887) and member of the Victorian Legislative Council (1902–1904)
 * William Cain (sea captain) (1862–1932), Manx master mariner
 * Sir William Cain, 1st Baronet (1864–1924), English brewer and philanthropist
 * William Cain (cricketer) (1899–1981), Australian cricketer
 * William Cain (deemster) (1935–2021), Manx judge
 * Bill Cain (athletic director) (fl. 1975–1980), American athletic director
 * Bill Cain (basketball) (fl. 1970), player in Iowa State Cyclones men's basketball
 * Bill Cain (fl. 1990s–2000s), American playwright