The Torchwood Institute, or simply Torchwood, is a fictional secret organisation from the British science fiction television series Doctor Who and its spin-off series Torchwood. It was established in 1879 by Queen Victoria after the events of "Tooth and Claw". Its prime directive is to defend Earth against supernatural and extraterrestrial threats. It is later revealed in "Army of Ghosts" that the Torchwood Institute has begun to use their findings to restore the British Empire to its former glory. To those ends, the organisation started to acquire and reverse engineer alien technology. Within Torchwood, an unofficial slogan evolved: "If it's alien, it's ours". According to one base director, Yvonne Hartman, its nationalist attitude includes refusing to use metric units.

Torchwood is a British science fiction television programme created by Russell T Davies. A spin-off of the 2005 revival of Doctor Who, it aired from 2006 to 2011. The show shifted its broadcast channel each series to reflect its growing audience, moving from BBC Three to BBC Two to BBC One, and acquiring American financing in its fourth series when it became a co-production of BBC One and Starz. Torchwood is aimed at adults and older teenagers, in contrast to Doctor Who's target audience of both adults and children. As well as science fiction, the show explores a number of themes, including existentialism, LGBTQ+ sexuality, and human corruptibility.