Thomas-Joseph Bouquillon (16 May 1840 in Warneton, Belgium – 5 November 1902 in Brussels, Belgium) was a Belgian Catholic theologian.
At the time of his death, he was professor of moral theology in the Catholic University of America.
He was one of the most eminent theologians of his time, a man of prodigious erudition in theology, history of theology, church 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.
He warned against appeals to Rome in moral matters when that substituted for grappling with the issues.