Sir William Aton (died before March 1389), sometimes called Baron Aton, of West Ayton, Barlby, South Holme and North Holme, Welham, Langton, Wintringham, Malton and Knapton in Yorkshire, was an English landowner, soldier and administrator who in 1371 was summoned to Parliament as a baron.

[1] Born about 1299, he was the son and heir of Sir Gilbert Aton, who died after 10 April 1350.

[1] About 1320, when he reached his majority, he was created a knight[1] and it is assumed that he later participated in the wars of King Edward III in France.

By later theory this created a hereditary barony, but there is no record of him attending further sessions and he continued to call himself Sir William Aton, knight.

In 1386, recording his age as 87 and saying he had been a knight for 66 years (but not a baron), he was a witness in the celebrated case of Scrope v Grosvenor.