Unforgotten is a British crime drama television series, which initially aired on ITV on 8 October 2015. It is written by creator Chris Lang and directed by Andy Wilson. The programme follows two London detectives, DCI Cassie Stuart (Nicola Walker) and DI Sunny Khan (Sanjeev Bhaskar), as they solve cold cases of disappearance and murder.

Three series, each consisting of six episodes, have been broadcast in the UK, as of August 2018. Each series deals with a new case, introducing seemingly unconnected characters who are gradually revealed to have some relationship with the victim. As the murder mystery unfolds, the emotional ramifications of the crime are also explored in the lives of those affected. Sometime after the third series finished ITV announced that a fourth series was to be made, and is expected to air sometime in 2019.

Unforgotten has received critical acclaim, with Tom Courtenay winning the 2016 BAFTA TV Award for Best Supporting Actor for the first series, and Mark Bonnar winning the 2017 BAFTA Scotland for Best Actor in Television for the second series.