"A Christmas Carol" is an episode of the British science fiction television programme Doctor Who. It is the sixth Doctor Who Christmas special since the programme's revival in 2005, and it was broadcast on 25 December 2010 on both BBC One and BBC America, making it the first episode to premiere on the same day in both the United Kingdom and United States. It was written by Steven Moffat and directed by Toby Haynes.

In the episode, a crashing space liner with more than four thousand people on board has been caught in a strange cloud belt. The alien time traveller the Doctor (Matt Smith) lands on the planet below and meets the miserly Kazran Sardick (Michael Gambon), a man who can control the cloud layer but refuses to help. Inspired by Charles Dickens's 1843 novella A Christmas Carol, the episode has the Doctor attempting to use time travel to alter Kazran's past and make him kinder so that he will save the spaceship.

Moffat enjoyed writing the episode and was a fan of Dickens' story himself. The story features flying sharks and fish, which were things Moffat was afraid of as a child. The episode features the acting debut of Welsh singer Katherine Jenkins, who also sang in the episode with a song written specifically for her. "A Christmas Carol" was filmed through July and August 2010 mainly on sets designed by the show's new set designer Michael Pickwoad. The special was seen by 12.11 million viewers in the UK and received generally positive reviews from critics.