The Tunnel (French: Tunnel) is a British–French crime drama television series adapted from the 2011 Danish–Swedish crime series The Bridge (Bron/Broen). The series began broadcasting on 16 October 2013 on Sky Atlantic in the UK, and on 11 November 2013 on Canal+ in France. The series stars Stephen Dillane and Clémence Poésy as British and French police detectives Karl Roebuck and Elise Wassermann. The plot follows the two detectives working together to find a serial killer who left the upper half of a French politician and the lower half of a British prostitute in the Channel Tunnel at the midpoint between France and the UK. The killer is nicknamed the "Truth Terrorist" and is on a moral crusade to highlight many social problems, terrorising both countries in the process. As the series progresses, the killer's true intention is revealed.

The Anglo–French adaptation of The Bridge was announced as a joint project between Sky and Canal+ in January 2013. Tunnel head writer Ben Richards worked with Hans Rosenfeldt, the creator of the original series. Due to the setting, the dialogue of the series is bilingual, a first for a British / French television co-production. Filming took place between February and August 2013 with a budget of £15 million, and was shot on location in Kent, England and Nord-Pas-de-Calais, France. It was produced with both British and French crew members. The premieres on both Sky Atlantic and Canal+ received strong ratings for the respective channels, with an initial consolidated figure of almost 900,000 in the UK and 1.3 million in France. Critical reception of the series has been generally positive, with Dillane and Poésy's acting being praised, as well as the plot's grittiness. Some reviewers made favourable comparisons with The Bridge, though others criticised The Tunnel for being identical. The producers admit that the first episode is a copy of the original.

On 16 February 2015, Canal+ and Sky Atlantic announced that a second series would begin production in March, set to air in early 2016, entitled The Tunnel: Sabotage, and consisting of eight episodes. Series 2 would focus on the crash of an airliner into the English Channel, with Dillane and Poésy returning; it premiered on Canal+ on 7 March 2016. The debut on Sky Atlantic was originally set for 5 April 2016 but was put off until a week later in deference to the Brussels terrorist attacks on 22 March 2016. It premiered in the UK on 12 April 2016 and was made available via Sky's On Demand service.

The renewal for a third and final series was announced on 20 January 2017 entitled The Tunnel: Vengeance and consisting of six episodes. It began filming in March 2017 and premiered on Sky Atlantic on 14 December 2017, with all episodes released on the same day. Canal+ did not announce a corresponding date for France at the time of the UK release. Season 3 premiered on Canal+ on 4 June 2018.

In the United States, the first season aired on many PBS stations from June through August 2016. The second season was broadcast from June through August 2017. The third season aired July through August 2018.