John Plunket or Plunkett may refer to:

• John Plunket (judge) (c. 1497–1582), Irish politician and judge, Lord Chief Justice of Ireland
• John Plunket (Jacobite) (1664–1738), Irish Jacobite
• John Plunket, 3rd Baron Plunket (1793–1871), Irish peer and Queen's Counsel
• John Plunkett (1802–1869), Attorney-General of New South Wales
• John Plunkett, 17th Baron of Dunsany (1853–1899), Anglo-Irish politician and peer
• John Plunkett, 3rd Baron of Dunsany (died 1500), Anglo-Irish nobleman