Andover Theological Seminary (1807–1965) was a Congregationalist seminary founded in 1807 and originally located in Andover, Massachusetts on the campus of Phillips Academy. From 1908 to 1931, it was located at Harvard University in Cambridge. It then collocated to Newton with Newton Theological Institution (NTI). Andover Theological Seminary and NTI formally merged in 1965 to form the Andover Newton Theological School (1965–2018). In its original and merged forms, it is the first and thus the oldest theological seminary founded in the United States. The seminary continues as Andover Newton Seminary at Yale Divinity School launched in 2017.
Andover Theological Seminary traces its roots to the late 18th century and the desire for a well-educated clergy among Congregationalists in the United States. That desire was expressed in the founding of Phillips Academy in 1778 for "the promotion of true Piety and Virtue".
In 1806, a growing split within the Congregational churches, known as the Unitarian Controversy, came to a full boil on the campus of Harvard College. The Hollis Chair of Divinity sat empty at Harvard for two years owing to tensions between liberal and more orthodox Calvinists. This theological battle soon divided many of the oldest churches in Massachusetts and began to impact church polity and the hiring of ministers. When the Harvard Board of Overseers appointed well-known liberal[ citation needed ] Henry Ware to the Hollis Chair in 1805, the Calvinists withdrew to organize and establish a new school in 1807, Andover Theological Seminary on the campus of Phillips Academy (est. 1778) in Andover, Massachusetts. This act, covered widely in the national press, was one of the significant events that contributed to the split in the denomination and to the eventual founding of the American Unitarian Association in 1825 (which joined the Universalists, founded in 1793, to become the Unitarian Universalist Association in 1961).
Andover was founded by the joint efforts of traditionalist, "Old Calvinists" and the adherents of the New Divinity (also known as New England theology) which was more revivalistic. Leonard Woods, Moses Stuart, and Edward Dorr Griffin were early faculty. 
Between 1886 and 1892, a theological dispute known as the "Andover Controversy" broke out between the conservative "New England Calvinism" of the founders and the liberal theology of many on the faculty. President E. C. Smyth was investigated and dismissed for his liberal views in 1887, but in 1891 his dismissal was reversed, on technical grounds, by the Massachusetts Supreme Court, and the matter was dropped the following year. 
In 1908, Harvard Divinity School and Andover attempted to reconcile, and the seminary moved its faculty and library to the Harvard campus (and soon into Andover Hall ). Plans for a formal affiliation between the academies were made, but the Supreme Judicial Court of Massachusetts disallowed the alliance since Andover's endowment is designated for a Christian theological education. Andover, therefore, relocated to the campus of Newton Theological Institution in 1931.
Andover Theological Seminary and the Newton Theological Institution formally merged in 1965 as the Andover Newton Theological School (ANTS). Newton Theological Institution began instruction in 1825 at Newton Centre, Massachusetts as a graduate seminary formally affiliated with the group now known as American Baptist Churches USA, the oldest Baptist denomination in America. As the institution developed, it adopted Andover's curricular pattern and shared the same theological tradition of loyalty to the evangelical Gospel and zeal for its dissemination.
In November 2015, ANTS announced that it would sell its campus and relocate to Yale Divinity School, after a presence of 190 years on that site. 
Prior to the founding of Andover and Newton, the model for the training of clergy was based on an undergraduate degree (actually the basis for the founding of most of the early colleges in the United States). The graduate model and the three year curriculum with a resident student body and resident faculty pioneered at Andover and Newton has become the standard for almost all of the 140 Protestant theological schools in the country.
Reflecting that zeal, the modern missionary movement began in this country through a group of Andover students known as the Brethren. Both Andover and Newton quickly assumed leadership in the modern mission movement, drawing the two schools into close association of people and ideas. Graduates such as Luther Rice and Hiram Bingham pioneered in Christian missions around the world. Adoniram Judson, an 1810 Andover alumnus, is best known for his work in Burma, where he translated the Bible into Burmese and produced the first Burmese-English dictionary.
Alumni of Andover Theological Seminary include the following notables, listed in order of their last year at the Seminary.
Gordon–Conwell Theological Seminary (GCTS) is an evangelical seminary with its main campus in Hamilton, Massachusetts, and three other campuses in Boston, Massachusetts; Charlotte, North Carolina; and Jacksonville, Florida. According to the Association of Theological Schools, Gordon-Conwell ranks as one of the largest evangelical seminaries in North America in terms of total number of full-time students enrolled.
Adoniram Judson was an American Congregationalist and later Particular Baptist missionary, who served in Burma for almost forty years. At the age of 25, Judson was sent from North America to preach in Burma. His mission and work with Luther Rice led to the formation of the first Baptist association in America to support missionaries.
Harvard Divinity School (HDS) is one of the constituent schools of Harvard University in Cambridge, Massachusetts. The school's mission is to educate its students either in the academic study of religion or for leadership roles in religion, government, and service. It also caters to students from other Harvard schools that are interested in the former field. HDS is among a small group of university-based, non-denominational divinity schools in the United States.
Judson College was a private women's college in Marion, Alabama. It was founded in 1838 and suspended its academic operations on July 31, 2021.
Francis Wayland, was an American Baptist minister, educator and economist. He was president of Brown University and pastor of the First Baptist Church in America in Providence, Rhode Island. In Washington, D.C., Wayland Seminary was established in 1867, primarily to educate former slaves, and was named in his honor.
The Meadville Lombard Theological School is a Unitarian Universalist seminary in Chicago, Illinois.
Myanmar Institute of Theology (MIT) is a Baptist theological institute in Insein Township, Yangon, Myanmar (Burma). Judson Research Center, Peace Studies Center, and Gender Studies Center are parts of Myanmar Institute of Theology. It is affiliated with the Myanmar Baptist Convention.
Cobb Divinity School was a Baptist theological institute. Founded in 1840, it was a Free Will Baptist graduate school affiliated with several Free Baptist institutions throughout its history. Cobb was part of Bates College in Lewiston, Maine, United States from 1870 until 1908 when it merged with the college's Religion Department.
Colgate Rochester Crozer Divinity School is a Baptist seminary in Rochester, New York It is affiliated with the American Baptist Churches USA.
James Luther Adams (1901–1994), an American professor at Harvard Divinity School, Andover Newton Theological School, and Meadville Lombard Theological School, and a Unitarian parish minister, was the most influential theologian among American Unitarian Universalists in the 20th century.
Newton Theological Institution was a Baptist theological seminary founded on November 28, 1825 in Newton Centre, Massachusetts.
Adoniram Judson "A. J." Gordon (1836–1895) was an American Baptist preacher, writer, composer, and founder of Gordon College and Gordon–Conwell Theological Seminary.
Andover Newton Theological School (ANTS) was a graduate school and seminary in Newton, Massachusetts. Affiliated with the American Baptist Churches USA and the United Church of Christ. It was the product of a merger between Andover Theological Seminary and Newton Theological Institution. In recent years, it was an official open and affirming seminary, meaning that it was open to students of same-sex attraction or transgender orientation and generally advocated for tolerance of it in church and society.
Bangor Theological Seminary was an ecumenical seminary, founded in 1814, in the Congregational tradition of the United Church of Christ. Located in Bangor, Maine, and Portland, Maine, it was the only accredited graduate school of religion in Northern New England
Lucius Bolles, D.D., S.T.D., sixth child of Rev. David Bolles, was born at Ashford, Connecticut. He was an 1801 graduate of Brown University and a student of theology three years with Dr. Samuel Stillman, of Boston, Massachusetts. He served more than 22 years as pastor of the First Baptist Church of Salem, Massachusetts, and Corresponding Secretary of the Baptist Board of Foreign Missions fourteen years. He was one of the founders of Newton Theological Institution.
Samuel Newell (1784–1821) was an American missionary and one of the pioneers of American foreign missions. He served with the American Board of Commissioners for Foreign Missions in India and Ceylon, where he founded the first American Ceylon Mission station.
Samuel Nott was one of the pioneers of American foreign missions. He was one of the first five foreign missionaries under American Board of Commissioners for Foreign Missions to India, and established Bombay Mission station, the first Americans overseas mission station at Bombay, then-headquarters of the Bombay Presidency.
David Newton Sheldon was the fifth President of Colby College, Maine, United States from 1843–1853. He was also a pastor, missionary, and educator.
Congregationalism in the United States consists of Protestant churches in the Reformed tradition that have a congregational form of church government and trace their origins mainly to Puritan settlers of colonial New England. Congregational churches in other parts of the world are often related to these in the United States due to American missionary activities.
Andover Newton Seminary at Yale Divinity School is an American seminary program founded in 2017 within Yale Divinity School and located in New Haven, Connecticut. It is the successor institution of Andover Newton Theological School (ANTS), the oldest graduate seminary in the United States and the nation's first graduate institution of any kind.