Amory Dwight Mayo (31 January 1823 - 8 April 1907) was a Unitarian clergyman and educator.
Mayo was born in Warwick, Massachusetts, the son of Amory Mayo and Sophronia Cobb. He enrolled at Amherst College in 1843. During his freshman year, illness forced him to leave school. For a short time he taught at district schools, but interest in the ministry led him to begin studying theology with Rev. Hosea Ballou II. By 1846, Mayo was an ordained Universalist minister.
Mayo's first congregation was in Gloucester. His preaching style, according to his parishioners, was appealing, enlightening, and spiritually uplifting, and his popularity led to ever-increasing church attendance. Mayo's health, however, was unsteady, sometimes preventing him from delivering church services. Nevertheless, many of his sermons were collected in his works The Balance; or, Moral Arguments for Universalism (1847) and Graces and Powers of the Christian Life (1853). These books provided continued Christian growth and spiritual illumination both for his congregation and future Christians.
In 1846, while serving as minister at Gloucester, Mayo married Sarah Edgarton (Sarah Carter Edgarton Mayo), who was noted for her literary accomplishments. Sarah died only two years after their marriage. In 1853 Mayo married Lucy Caroline Clarke. Mayo had five children.
In October 1854 Mayo resigned his pastoral duties at Gloucester, responding to an invitation to become pastor of the Independent Christian Church in Cleveland, Ohio, where he served for the next two years. This appointment was less fruitful than he expected, and in 1856 he relocated to Albany, New York, where he ministered at the Division Street Unitarian Church until 1863. While there he delivered the dedication address for the Green Hill Cemetery. His address linked cemeteries to the mission of creating a Christian Republic. In 1859 he published the book Symbols of the Capital: Civilization in New York. In 1863 he accepted a position as preacher of the Church of the Redeemer in Cincinnati, Ohio.