Oliver Joseph St. John Gogarty was an Irish poet, author, otolaryngologist, athlete, politician, and conversationalist. He served as the inspiration for Buck Mulligan in James Joyce's novel Ulysses.

Malachi Roland St. John "Buck" Mulligan is a fictional character in James Joyce's 1922 novel Ulysses. He appears most prominently in episode 1 (Telemachus), and is the subject of the novel's famous first sentence: "Stately, plump Buck Mulligan came from the stairhead, bearing a bowl of lather on which a mirror and a razor lay crossed."