The Paulist Fathers, officially named the Missionary Society of Saint Paul the Apostle, abbreviated CSP, is a Catholic society of apostolic life of Pontifical Right for men founded in New York City in 1858 by Isaac Hecker in collaboration with George Deshon, Augustine Hewit, and Francis A. Baker.

Isaac Thomas Hecker was an American Catholic priest and founder of the Paulist Fathers, a North American religious society of men.