William O'Callaghan

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