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.

Harvey Gallagher Cox Jr. is an American theologian who served as the Hollis Professor of Divinity at Harvard Divinity School, until his retirement in October 2009. Cox's research and teaching focus on theological developments in world Christianity, including liberation theology and the role of Christianity in Latin America.