Teen Big Brother: The Experiment also known as Teen Big Brother is a United Kingdom reality television spin off of the show Big Brother where a group of teenagers lived in the Big Brother House for ten days. It was pre-recorded on 30 July – 8 August 2003 shortly after the fourth series of Big Brother ended and was aired on Channel 4 over five nights on 13–17 October 2003. The program consisted of five episodes, each approximately 60 minutes long including adverts, with Elaine Hackett serving as executive producer for Endemol UK Productions. Channel 4 announced the series on 22 May 2003 for the broadcaster’s educational division 4Learning with the aim of transmitting the series in late 2003 or early 2004. The series was controversial as some felt the broadcaster was exploiting the teenagers while the program featured the first sexual act between two contestants in the history of the British adaptation of Big Brother.

The series followed a similar format to its parent show where the contestants, known as Housemates, lived inside a specialty built compound known as the Big Brother House at Elstree Studios. The Housemates were constantly filmed during their time in the House and were not permitted to speak with those filming them. Due to the pre-recorded nature of the programme the viewing public was unable to vote during evictions and decide the winner instead the Housemates did all the voting during their time in the House. The Housemates competed to win a trip around the world worth £30,000 which was won by Paul Brennan after he was crowned the winner with a majority vote from his Housemates. Brennan chose to share his prize with Caroline Cloke, the runner-up.