Mather Byles (1706-1788), American clergyman, was born in Boston, Massachusetts, on the 26th of March 1706, descended, on his mother's side, from John Cotton and Richard Mather. He graduated at Harvard in 1725, and in 1733 became pastor of the Hollis Street church (Congregational), Boston. He held a high rank among the clergy of the province and was noted for his scholarly sermons and his ready wit. At the outbreak of the War of Independence he was outspoken in his advocacy of the royal cause, and after the British evacuation of Boston his connexion with his church was dissolved. He remained in Boston, however, and subsequently (1777) was arrested, tried and sentenced to deportation. This sentence was later changed to imprisonment in his own house. He was soon released, but never resumed his pastorate. He died in Boston on the 5th of July 1788. Besides many sermons he published A Poem on the Death of George I. (1727) and Miscellaneous Poems (1744).

His son, Mather Byles (1735-1814), graduated at Harvard in 1751, and was a Congregational clergyman at New London, Connecticut, until 1768, when he entered the Established Church, and became rector of Christ church, Boston. Sympathizing with the royal cause, he settled, after the War of Independence, in St Johns, New Brunswick, where he was rector of a church until his death.