Thomas-Joseph Bouquillon (1840–1902) was a Belgian Catholic theologian and priest. He was the first professor of moral theology at the Catholic University of America and introduced social sciences into the curriculum. Regarded as a prominent Catholic theologian of his time, his contributions focus in theology, history of theology, ecclesiastical history, canon law, and bibliography. Bouquillon was active and influential in the organization of the Catholic universities of Lille and Washington; he supported the views of Archbishop John Ireland and Edward McGlynn.