Ultimate Big Brother was the final series of the UK reality television programme Big Brother to air on Channel 4. The series was broadcast for 18 days, from 24 August 2010 to 10 September 2010 and was produced by Remarkable Pictures, a division of Endemol. It featured memorable housemates from previous series of Big Brother, and a smaller section of housemates from Celebrity Big Brother. A 24-hour live streaming service was also available via the Big Brother website as a fee-based service. The series ended with Brian Dowling winning the title of the "Ultimate Housemate" and the words "Big Brother will get back to you".
The series was first announced during the launch night of the eleventh series of Big Brother. The first trailer for Ultimate Big Brother was shown on 13 August 2010 during a live eviction episode of Big Brother. On the same day, Channel 4 released a promo image for the series on the Big Brother website. The promo featured 15 of the previous 186 Big Brother housemates and 68 Celebrity Big Brother housemates, along with the tag line "Who goes in? We decide".
The Launch Night and first broadcast of Ultimate Big Brother was on 24 August 2010 as part of the Big Brother 11 final night show, presented by Davina McCall.
The main television coverage of Ultimate Big Brother was screened on Channel 4 using daily highlights programmes, narrated by Marcus Bentley. These episodes summarised the events of the previous day in the House. Although the schedule was erratic, in general the Monday to Thursday highlights episodes were shown at 10pm and aired for 70 minutes, whilst the weekend shows aired for 60 minutes at 9pm. The two-part, live eviction shows, hosted by Davina McCall, featured a highlights episode 9pm and a second show at 10.35pm in which the evicted housemate (or housemates) were interviewed. Eviction shows and highlights episodes were given a censored repeat the following morning on both Channel 4 and E4.