Derrick O'Connor (born 1941) is an Irish character actor, mostly known for his roles in Terry Gilliam films. He was a member of the Royal Shakespeare Company.

Terry Gilliam, who has directed O'Connor on three films, has noted in his audio commentaries that Derrick seems to have a habit of taking away most of his dialogue in favor of physical character humor. Notable examples include Time Bandits, in which his characters' dialogue was resorted to simple grunts while the Maid Marian character "translated" for him and in Brazil, in which Derrick scrapped all of his character's dialogue and simply repeated the dialogue of Bob Hoskins' character.

Derrick O'Connor was born in Dublin, Ireland, and raised in London, UK. He currently resides with his family in San Francisco, CA. He is a former member of the Royal Shakespeare Company and the Scottish National Theatre, with many leading stage performances in Edinburgh, Stratford-on-Avon and London's West End. His long and successful career includes numerous starring roles in U.S., British and Australian film and television. O'Connor supports independent filmmaking as an important platform for emerging talent, to ensure a healthy future for the film industry. Projects he has worked on include Seascape (1994) (TV) and First Vampire: Don't Fall for the Devil's Illusions, The (2004). O'Connor has been seen most recently by American audiences in the feature films Daredevil (2003), End of Days (1999), How to Make an American Quilt (1995) and Lethal Weapon 2 (1989). His many American TV guest appearances include "Alias" (2001), Tracey Ullman's "Tracey Takes On..." (1996) and "Murder, She Wrote" (1984). British film credits include Terry Gilliam's Brazil (1985), Time Bandits (1981) and Jabberwocky (1977), John Boormans Hope and Glory (1987), Harold Pinter's Butley (1974) and Dealers (1989).