Gavin & Stacey is a British sitcom created, written by and starring James Corden and Ruth Jones about two families: one from Billericay in Essex, and the other from Barry in the Vale of Glamorgan. Mathew Horne and Joanna Page play the eponymous characters Gavin and Stacey, while Corden and Jones star as their respective friends Smithy and Nessa. Alison Steadman and Larry Lamb co-star as Gavin's parents Pam and Mick, Melanie Walters plays Stacey's mother Gwen, and Rob Brydon plays Stacey's uncle Bryn.

Baby Cow Productions produced the sitcom for BBC Cymru Wales. The first series, consisting of six episodes, premiered on BBC Three in May 2007 to positive reviews and strong ratings. It returned for a second series of seven episodes in March 2008, before being transferred to BBC One for a Christmas Eve special, due to the show's growing mainstream popularity. The third and final series aired from 26 November 2009 to 1 January 2010, forming a significant part of the prime-time BBC Christmas programming for 2009.

Gavin & Stacey was directed by Christine Gernon, who had previously directed other BBC sitcoms such as One Foot in the Grave. Acclaimed as both a hit and a breakthrough show for the BBC, it was the most nominated show in the 2007 British Comedy Awards. It won several awards, including the British Academy Television Awards (BAFTA) Audience Award, and the British Comedy Awards Best TV Comedy Award, both in 2008. In 2019, Gavin & Stacey was named the 17th-greatest British sitcom in a poll by Radio Times.

Corden and Jones wrote another Christmas special, which aired on 25 December 2019. With 18.49 million total viewers (11.6 million overnight), the broadcast in the United Kingdom was the most-viewed non-sporting event in a decade and the most-watched comedy in 17 years. The final episode of Gavin & Stacey aired on 25 December 2024, 17 years after the show was first broadcast. The finale was the most-watched scripted show in over two decades.