Dennis O'Neil (A.K.A. Denny O'Neil) is a comic book writer and editor, principally for Marvel Comics and DC Comics in the 1970s.

His best works include Green Lantern/Green Arrow and Batman with Neal Adams, The Shadow with Mike Kaluta and The Question with Denys Cowan , all of which were hailed for sophisticated stories that expanded the artistic potential of the mainstream portion of the medium. As an editor, he is principally known for editing Batman.