John Callaghan

John Callaghan may refer to:

• John Callaghan (physician) (1923–2004), Canadian cardiac surgeon
• John Callaghan (Galway), Irish murder victim
• John Callaghan (musician) (born 1969), British musician
• John Callaghan (screenwriter), see List of Republic of Doyle episodes
• John Callaghan (footballer), see List of Sheffield Wednesday F.C. players