Big Brother 2007, also known as Big Brother 8, was the eighth series of the British reality television series Big Brother, airing on Channel 4, with a number of closely associated programmes also airing on E4. The series launched on 30 May 2007 hosted by Davina McCall and ended 94 days later on 31 August 2007, making it the longest running series of Big Brother in the UK. Ratings for this series were at their lowest at the time, with the series averaging 3.8 million viewers.

The launch night was unique in that all the housemates who entered where female, with the male housemates arriving sparingly over the first two weeks. An additional five housemates entered the house in Day 59. They went to a new house next door called "The Halfway House".

A number of changes had been made to the show, including the omission of text message voting, and a reduction in the cost of calls to vote for evictions from 50p to 25p. At least 10p from each vote was going to charity.

This was the first Big Brother series to air in the UK since the highly controversial Celebrity Big Brother 5, as a result, a number of strict rules were applied to avoid a further controversy. Controversy hit the show on Day 8, when Emily Parr was removed from the house in the early hours of the morning after calling Charley Uchea a nigger; although she did not use it in an argument and the two appeared to be friends, a decision was made to remove her immediately.