Jonathan Firth (born April 6, 1967) is a British actor.

Jonathan is the younger brother of Colin Firth. He was born in Essex. He has played in cinematic movies and also has some notable TV-appearances. In 2003, he played in the BBC's dramatized documentary Pompeii: The Last Day. It must be noted Firth seems to have a liking for detective-series; he has starred in Inspector Morse (1987), Poirot (1989), Cadfael (1994), Midsomer Murders (1997) and The Inspector Lynley Mysteries (2002).