Alan Ansen (January 23, 1922 – November 12, 2006) was an American poet, playwright, and associate of Beat Generation writers. He was a widely read scholar who knew many languages. Ansen grew up on Long Island and was educated at Harvard. He worked as W. H. Auden's secretary and research assistant in 1948-49; he was the main author of the chronological tables in Auden's The Portable Greek Reader and Poets of the English Language.

He became a close friend of various Beat writers, and was the model for flamboyant characters in their fiction, including Rollo Greb in Jack Kerouac's On the Road, AJ in William S. Burroughs' Naked Lunch, and Dad Deform in Gregory Corso's American Express. Ansen spent time in Tangiers with Paul Bowles and was a close associate of Allen Ginsberg.

Ansen lived mostly in Athens after the early 1960s, where he was part of a circle of writers that included James Merrill and Chester Kallman.