Harvard Divinity School Library holds the papers of many prominent theological scholars, including preeminent Unitarian minister William Ellery Channing, twentieth-century theologians Paul Tillich and H. Richard Niebuhr, and New Testament scholar Caspar René Gregory. The Tillich collection is particularly noteworthy, as it contains drafts of all of his major works, 100 boxes of correspondence with major figures of the time, and rare photographs.

The library also holds the papers of Harvard Divinity School faculty, including collections on James Freeman Clarke, a pioneer in the field of comparative theology; Samuel Miller, former HDS Dean; Henry Wilder Foote, historian and hymnologist; and Gordon Kaufman, longtime professor of theology.