Orville Dewey (March 28, 1794 – March 21, 1882) was an American Unitarian minister.
He was born in Sheffield, Massachusetts. His ancestors were among the first settlers of Sheffield, where he spent his early life, alternately working upon his father's farm and attending the village school. He was naturally thoughtful, and was encouraged in his love of reading by his father. His mother's piety had great influence in the formation of his character. The strict Calvinism that colored the religious life around him was greatly tempered by his intercourse with his cousin, Paul Dewey, who was an able mathematician and a skeptic with regard to the prevailing theology.
His parents had him so thoroughly prepared for College that he entered the sophomore class in Williams College, where he was graduated in 1814. He then returned to Sheffield, where he engaged in teaching, and afterward went to New York, becoming a clerk in a dry goods house. He was graduated at Andover Theological Seminary in 1819, and for eight months was agent for the American education society, having declined an immediate and permanent pastorate on account of his unsettled views regarding theology.
Notwithstanding a very candid expression of his opinions, he was offered a pulpit in Gloucester, which he accepted temporarily. He soon became a Unitarian, and was appointed to be the assistant of Dr. William Ellery Channing, in Boston, with whom he formed a lasting friendship, and whose Church he supplied during its pastor's travels in Europe.
In 1823 he became pastor of the Unitarian Church in New Bedford, remaining there for ten years, until he went to Europe on account of his health. He was called to the second Unitarian Church of New York in 1835, which during his ministry built the Church of the Messiah. In 1840, he was elected into the National Academy of Design as an Honorary Academician. In 1842 his health again failed, and he went a second time to Europe, returning in 1844.