Mike Gwilym (born Michael Gwilym, 5 March 1949) is a Welsh actor born in Neath. He is the elder brother of actor Robert Gwilym, known to television audiences for playing Max in the BBC series Casualty.
Gwilym began acting while a student at Oxford University, performing with the Oxford University Dramatic Society, before joining the Glasgow Citizens' Theatre and later becoming an associate actor of the Royal Shakespeare Company. His stage debut came as Prince Hal in Henry IV, Part 1 at the Playhouse Theatre, Sheffield, in 1969, and he went on to appear in many RSC productions during the late 1970s and early 1980s, including The Comedy of Errors, King Lear, Troilus and Cressida and Love's Labour's Lost.
His best-known screen role came as jockey-turned-investigator Sid Halley in The Racing Game (1979), a Yorkshire Television adaptation of Dick Francis's novel Odds Against. Film credits include Hopscotch (1980), Venom (1981) and Priest of Love (1981), and he starred opposite his brother Robert as one of a pair of Welsh twins in On the Black Hill (1988), adapted from Bruce Chatwin's novel of the same name and largely filmed around Hay-on-Wye. He also appeared in the BBC Television Shakespeare series, playing Aufidius in Coriolanus, Berowne in Love's Labour's Lost and the title role in Pericles, Prince of Tyre.
Gwilym later stepped back from the professional stage and moved to southern Spain, where his family had long kept a summer home.