The Grand Knockout Tournament (also known as It's a Royal Knockout) was a one-off charity event which took place on 15 June 1987, and was shown on British television on 19 June 1987 (BBC1, repeated on 27 December 1987), in addition to airing on American TV via the USA Network on 12 August 1987, and European satellite channel Superchannel on 6 March 1988 (repeated on Christmas Day 1988).

The event was staged on the lakeside lawn of the Alton Towers stately home and theme park in Staffordshire. It followed the format of It's a Knockout (the British version of Jeux sans frontières), a slapstick TV game show which was broadcast in the UK until 1982. The show featured members of the British royal family alongside various sporting and showbiz celebrities. The celebrity participants were drawn from the realms of music, sport, television, comedy and film.

Although regarded as a failure, a similar show without royal involvement was made the following year at Walt Disney World in Florida, featuring teams of celebrities representing the United Kingdom, USA and Australia.