Rex the Runt is a stop-motion adult animated claymation pixilation comedy series, primarily consisting of a television show and two short films produced by Aardman Animations and Egmont Imagination for BBC Bristol, with EVA Entertainment co-producing the first series. Its main characters are four plasticine dogs: Rex, Wendy, Bad Bob and Vince.

Rex was first introduced as a minor character in Ident (1989), a short film directed by Richard Starzak for the Lip Synch series. During the seven years of development of the characters, Starzak produced three pilots, subtitled How Dinosaurs Became Extinct (1991), Dreams (1991) and North by North Pole (1996). The 1991 pilots were unknown to the Aardman crew at the time, as Starzak created them during his free time. Because of this, the series wasn't pitched until the discovery of these shorts a year later, as the team found potential to turn these shorts into a full-fledged series.

Thirteen ten-minute episodes of the series aired over two weeks on BBC Two from December 1998. A second, thirteen-episode series aired from September 2001 on the same channel. As well as the core cast, guest voices included Paul Merton, Morwenna Banks, Judith Chalmers, Antoine de Caunes, Bob Holness, Simon Day, Bob Monkhouse, Jonathan Ross, Graham Norton, Arthur Smith, June Whitfield, Kathy Burke, Pam Ayres and Eddie Izzard.

The animation is unusual in that the models are almost two-dimensional and are animated to exaggerate this - they are flattened in appearance and animated on a sheet of glass with the backgrounds behind the sheet. This would be altered in the second series, as the models would become more three-dimensional.