List of Torchwood episodes

Torchwood is a British science fiction television programme created by Russell T Davies for the British Broadcasting Corporation (BBC). Initially developed as a stand-alone show, it was reworked into a spin-off of the long-running television production Doctor Who. Originally targeted towards adult audiences, compared to the family-centric nature of its parent series, the first series of Torchwood was broadcast after-watershed. It premiered on BBC Three on 22 October 2006 and aired 13 episodes before concluding on 1 January 2007. A second series was commissioned thereafter with the programme moving to BBC Two. When Captain Jack Harkness, a central character in the show, became popular with younger audiences, alternative cuts of the second series were made which removed adult content allowing a broader audience to view the episodes. BBC Two broadcast the second series, also consisting of 13 episodes, between 16 January and 4 April 2008, although BBC Three aired seven first-run episodes from 13 February to 21 March.

In its final two series, Torchwood utilised serial storytelling rather than the monster of the week format that was present in the first two. The programme moved channels once more when a five-episode mini-series subtitled Children of Earth was broadcast on BBC One from 6 to 10 July in 2009. The fourth and final series became an American co-production with the U.S. premium cable network Starz. Subtitled Miracle Day, the 10-episode fourth series aired on Starz from 8 July until 9 September 2011, with each episode being broadcast on BBC One six days later.

Torchwood is an anagram of Doctor Who which was used as a title ruse during early production of the latter's 2005 revival process. The term was later seeded in that programme's second series. The show centres around the titular organisation called Torchwood. The institute employs several elite teams of black operatives that investigate extraterrestrial incidents on Earth. Torchwood specifically centres around one of these groups, Cardiff's Torchwood Three, which is led by Captain Jack Harkness, who was first introduced in Doctor Who's first series as a companion of the Ninth Doctor. He is assisted by support officer Ianto Jones, Dr. Owen Harper, technical expert Toshiko Sato, and Gwen Cooper, a police constable recruited to assist the team. They are further aided by former Tenth Doctor companion Martha Jones in the second series and Gwen's husband Rhys Williams, who becomes a main character beginning with series three. Miracle Day sees a partial overhaul in the cast with only Harkness, Cooper, and Williams remaining. The three are joined by special agent Rex Matheson and analyst Esther Drummond from the Central Intelligence Agency, as well as death row inmate Oswald Danes. Across all four series, Torchwood had a small number of crossovers with Doctor Who, making up two of the television series in the Whoniverse.

In 2012 the show was placed on an indefinite hiatus although Harkness continued to appear in Doctor Who with appearances in both 2020 and 2021. The first two series of Torchwood were led by Chris Chibnall as head writer while Davies returned as showrunner for the final two. Over its run, the show explored a number of themes; prominent among these were existentialism, homosexual and bisexual relationships, and explorations of human corruptibility. The programme also has a large amount of tie-in media leading to an expanded universe. It was also broadcast in several other countries gaining a cult following as well as strong viewing figures and international critical acclaim. During the course of the programme, 41 episodes of Torchwood aired over four series, between 22 October 2006 and 9 September 2011.