Mather Byles (born 26 March 1706, Boston, Massachusetts – 5 July 1788), was an American clergyman active in British North America. Byles was descended, on his mother's side, from John Cotton and Richard Mather and was a grandson of Increase Mather and nephew of Cotton Mather. As a young man, he corresponded with Alexander Pope and Isaac Watts. At the outbreak of the American Revolution, Byles was outspoken in his advocacy of the royal cause, and after the British evacuation of Boston his connection with his church was dissolved. Byles died in Boston on 5 July 1788, aged 82.