Thomas Ashwell or Ashewell (c. 1478 – after 1513 (possibly 1527?)) was an English composer of the Renaissance. He was a skilled composer of polyphony, and may have been the teacher of John Taverner.

His admission to St. George's Chapel as a chorister in 1491 suggests a birthdate of approximately 1478, but nothing else is known about his early life. He stayed at St. George's until 1493, and account records at Tattershall College in Lincolnshire list him as a singer there in 1502 and 1503. He was in a position of authority at Lincoln Cathedral in 1508, according to records there, and was employed at Durham Cathedral as Cantor or Master of the singing boys, and to provide music for the Lady Chapel, in 1513; no further records survive of his life. The Durham Cathedral archives show the first successor to his duties there as being a William Robson, who began his duties in 1527, and this may be an indication of Ashwell's death some time before that.