William Plunkett
William Plunkett may refer to:
- William Plunkett (highwayman), 18th-century British highwayman and associate of James MacLaine
- William C. Plunkett, lieutenant governor of Massachusetts
- William [Plunket, 1st Baron Plunket], Irish politician and lawyer who eventually became Lord Chancellor of Ireland
- William Plunket, 4th Baron Plunket, Church of Ireland Dean of Christ Church Cathedral and Archbishop of Dublin
- William Plunket, 5th Baron Plunket, British diplomat and administrator
- Billy Plunkett, Australian rules footballer for Geelong