Marion and Geoff is a BBC television mockumentary in video-diary format, produced by Baby Cow Productions and screened on BBC Two in 2000, with a second series following in 2003. The series starred Rob Brydon as Keith Barret, a naïve taxi driver going through a messy divorce from his wife, Marion, who, though he fails to realise it, has had a long-standing affair with her colleague, Geoff. Each episode is presented as a monologue, filmed by a fixed camera in the confines of his car.

The series were written by Brydon and Hugo Blick, and produced and directed by Blick. The associate producer was Steve Coogan.

The script is written in such a way that the viewer can pick up on clues that Keith has not himself realised. Numerous references are made to one of his children not resembling him very strongly, an obvious hint that one of the children he loves so dearly is not his own, but in fact Geoff's. Keith also gives clues in the first series about his wife's activities—the viewer knows about Marion's affair long before he works it out himself.

Keith's character is affectionately portrayed as a gentle dunce and draws a great deal of sympathy as the series progresses. He is in denial about his divorce, and somehow always manages to look on the positive side of even the most awful situation. Although he doesn't understand it, his life revolves around Marion and her new partner Geoff, and his love for his "little smashers" (his sons, Rhys and Alun). Despite his faults, Keith is a hard-working and good man.