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.

While described as "beyond the UN", the Torchwood Institute is seen to cooperate with UNIT to some extent. There appears to have been some rapport with the Prime Minister, although it is noted by Harriet Jones in "The Christmas Invasion" that she is not meant to know the existence of Torchwood. Those who have come into contact with Torchwood primarily believe it to be a special forces team. Torchwood maintains this illusion by using false witnesses, or by sectioning any journalists who threaten to expose the truth, and via the use of memory-altering drugs. Following a major incident which led to the destruction of Torchwood One, Jack Harkness rebuilds Torchwood to become less confrontational and more secretive in honour of the Doctor.