Doctor Foster is a British psychological thriller television series that debuted on BBC One on 9 September 2015. Created and written by Mike Bartlett, the series is about Gemma Foster (Suranne Jones), a doctor who suspects her husband Simon (Bertie Carvel) is having an affair. After she follows several lines of enquiry, she slowly begins to lose her sanity as her life unravels from what secrets she finds. The storyline was inspired by the ancient Greek myth of Medea, a wronged wife who kills her children and poisons her husband's new bride.

Internationally, the series was brought to many countries by different networks (see Broadcast).

The second series of the show started on 5 September 2017 and concluded on 3 October 2017. A future third series has been played down by lead actress Jones, citing incompatibility of schedules. Bartlett has said while there is more to explore with Gemma Foster's story, he would bring the show back only if there were a vital story to be told, with no immediate plans for a return. He did, however, write a spin-off, Life, featuring the character of Anna Baker from the first two series.