Dennis J. "Denny" O'Neil (born May 3, 1939 in St. Louis, Missouri) is an American comic book writer and editor, principally for Marvel Comics and DC Comics from the 1960s through the 1990s, and Group Editor for the Batman family of books until his retirement.
His best-known works include Green Lantern/Green Arrow and Batman with Neal Adams, The Shadow with Michael Kaluta and The Question with Denys Cowan, all of which were hailed for their sophisticated stories that expanded the artistic potential of the mainstream portion of the medium. As an editor, he is principally known for editing the various Batman titles. As of 2013, he sits on the board of directors of the charity The Hero Initiative and serves on its Disbursement Committee.