"The Mighty Atom" is an episode of Thunderbirds, a British Supermarionation television series created by Gerry and Sylvia Anderson and filmed by their production company AP Films for ITC Entertainment. Written by Dennis Spooner and directed by David Lane, it was first broadcast on 30 December 1965 on ATV Midlands as the 14th episode of Series One. It is the sixth episode in the official running order.