William O'Callaghan may refer to: William O'Callaghan (Irish Army officer) (1921–2015), Irish Army officer William Frederick Ormonde O'Callaghan (1852–1877), Irish MP William O'Callaghan (politician) (died 1967), Irish senator Bill O'Callaghan (1868–1946), hurler
See also William Callaghan (disambiguation)