Richard David Ellmann, FBA (March 15, 1918 – May 13, 1987), was an American literary critic and biographer of the Irish writers James Joyce, Oscar Wilde, and William Butler Yeats. He won the U.S. National Book Award for Nonfiction for James Joyce (1959), one of the most acclaimed literary biographies of the 20th century. Its 1982 revised edition won James Tait Black Memorial Prize. Ellmann was a liberal humanist, and his academic work focuses on the major modernist writers of the 20th century.

Ellmann was born in Highland Park, Michigan, the second of three sons of James Isaac Ellman, a lawyer, and his wife Jeanette (née Barsook). His father was a Romanian Jew and his mother was a Ukrainian Jew from Kyiv. Ellmann served in the United States Navy and Office of Strategic Services during World War II. He studied at Yale University, receiving his B.A. in 1939, his M.A. in 1941, and his PhD (for which he won the John Addison Porter Prize) in 1947. In 1947, he was awarded a B.Litt. degree (an earlier form of the M.Litt) by Trinity College Dublin, where he was resident while researching his biography of Yeats. As a Yale undergraduate at Jonathan Edwards College, Ellmann was a member of Phi Beta Kappa (scholastic honor society); Chi Delta Theta (literary honor society); and, with James Jesus Angleton, a member of the Executive Editorial Board of the Yale Literary Magazine. He achieved "Scholar of the Second Rank" (current equivalent: magna cum laude). The 1939 Yale Banner undergraduate yearbook published an untitled Ellmann account (similar in concept and style to Oscar Wilde's parables, which Ellmann cited in his 1987 biography Oscar Wilde) of a chagrined Joseph, husband of Mary, and Jesus Christ's custodial father:

Joseph was no match for the angel and for Mary's flattering tears. He felt a wince of disappointment at the idea that she had had a vision too, but then she was his wife, and perhaps the whole family now had the prophetic gift. He would have to try it out, on the harvest. Meanwhile he would seek to forget his jealousy, despite the fact that the story sounded a bit fantastic to a reasonable man, which he guessed he was, and it would be well not to talk about it much outside. It was better to leave things the way they were. Not much of a wedding night, but one could tell white lies about that to one's friends.

Ellmann later returned to teach at Yale, and there he and Charles Feidelson Jr. edited the anthology The Modern Tradition. He earlier taught at Northwestern and the University of Oxford before serving as Emory University's Robert W. Woodruff Professor from 1980 until his death.

He was Goldsmiths' Professor of English Literature at Oxford University, 1970–1984, then Professor Emeritus, a fellow at New College, Oxford, 1970–1987, and an extraordinary fellow at Wolfson College, Oxford, from 1984 until his death. He was also a Fellow of the British Academy. In 1983 he delivered the British Academy's Sarah Tryphena Phillips Lecture in American Literature and History.

Ellmann used his knowledge of the Irish milieu to bring together four literary luminaries in Four Dubliners: Wilde, Yeats, Joyce, and Beckett (1987), a collection of essays first delivered at the Library of Congress.

His wife, the former Mary Donoghue, whom he married in 1949, was an essayist. The couple had three children: Stephen (b. 1951), a South Africa constitutional scholar, Maud (b. 1954), and Lucy (b. 1956). The first two became academics and Lucy a novelist and writing teacher.

Ellmann died of motor neurone disease in Oxford on May 13, 1987, at the age of 69.