Thomas Ashton (died 29 August 1578, Cambridge) was an English clergyman and schoolmaster, the first headmaster of Shrewsbury School.
Ashton was originally identified with the Thomas Ashton who was educated at Cambridge University, where he graduated B.A. in 1559-60, and M.A. in 1563 This man was elected a fellow of Trinity College in 1562 and entered holy orders. This was the accepted identity of the first head master of Shrewsbury School at the time his sketch was written by Thompson Cooper for the first edition of the Dictionary of National Biography (1885).
However he was later identified with an earlier Thomas Ashton who graduated from St John's College, Cambridge as B.A. in 1520, M.A. in 1521 and B.Th. (Bachelor of Theology) in 1531. He was elected fellow of the college in 1520, of which he was still serving in 1542, and holding a benefice as a clergyman in the Diocese of Lincoln. This identification was accepted by 2004 when Martin E. Speight published his article on Ashton in the Oxford Dictionary of National Biography.
In 1562 he was appointed the first head master of Shrewsbury School. In April 1561, Bishop Bentham of Lichfield had requested the Archbishop of Canterbury, Matthew Parker, to license Ashton's non-residence at a parish living that was apparently away from Shrewsbury on the grounds restraining him would damage the progress of the school's foundation and that he was the only licensed preacher in the town.
Ashton raised Shrewsbury to a high position: while he was headmaster, there were as many as 290 pupils at a time. Among his pupils were Philip Sidney and Fulke Greville. William Camden, in his Britannia, remarked that "Shrewsbury is inhabited both by Welsh and English, who speak each other's language; and among other things greatly to their praise is the grammar school founded by them, the best filled in all England, whose flourishing state is owing to provision made by its head master, the excellent and worthy Thomas Ashton." The school drew pupils from sons of gentry in surrounding counties, the furthest being from Buckinghamshire and half the boys were boarded at homes in the town.