Doctor Who is a British science fiction television programme produced by the British Broadcasting Corporation. The programme depicts the adventures of a Time Lord, a time-travelling, humanoid alien known as the Doctor who explores the universe in a sentient, telepathic time machine called the TARDIS that flies through time and space, whose exterior appears as a blue police box from London in 1963, when the series first aired. Along with a succession of companions, he faces a variety of foes while working to save civilisations, help people and right wrongs.

It has received recognition from critics and the public as one of the finest British television programmes, including the BAFTA Award for Best Drama Series in 2006, and five consecutive wins at the National Television Awards from 2005 to 2010, in the Drama category while under Russell T Davies' reign as executive producer. In 2011 Matt Smith became the first actor to be nominated for a BAFTA for portraying the Doctor. The programme is listed in Guinness World Records as the longest-running science fiction television show in the world, and as the "most successful" science fiction series of all time, in terms of its overall broadcast ratings, DVD and book sales and iTunes traffic. It has been recognised for its imaginative stories, creative low-budget special effects during its original run, and pioneering use of electronic music (originally produced by the BBC Radiophonic Workshop). The show is a significant part of British popular culture in the United Kingdom, and elsewhere it has become a cult television favourite. The show has influenced generations of British television professionals, many of whom grew up watching the series. The programme originally ran from 1963 to 1989. After an unsuccessful attempt to revive regular production with a backdoor pilot in the form of a 1996 television film, the programme was relaunched in 2005, produced in-house by BBC Wales in Cardiff. The first series was produced by the BBC; series two and three had some development money contributed by the Canadian Broadcasting Corporation (CBC), which was credited as a co-producer. Doctor Who also spawned spin-offs in multiple media, including Torchwood, The Sarah Jane Adventures, K-9, P.R.O.B.E. (video series), and a single pilot episode of K-9 and Company in 1981.