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