Thomas Baily (c. 1525, Yorkshire - 7 October 1591, Douai) was an English Catholic clergyman during the Elizabethan persecutions.
Baily was an undergraduate at Clare College, Cambridge, where he graduated Bachelor of Arts in 1546.
About November, 1557, he was appointed Master of Clare College and in 1558 received the further degree of Bachelor of Divinity.
He next visited Louvain, where he remained until 30 January 1576, during the interval receiving the degree of Doctor of Divinity.
Baily was entombed in the Chapel of St. Emma the great within the parish church of St. James at Douai.