Celebrity Big Brother 2009, also known as Celebrity Big Brother 6, was the sixth series of Celebrity Big Brother. It was broadcast on Channel 4, launching on 2 January 2009 and running for 22 days until 23 January 2009. The launch show was watched by approximately 6.4 million people. Davina McCall returned as main presenter, with George Lamb as host of Big Brother’s Little Brother, and Jack Whitehall as host of Big Brother’s Big Mouth. The winner of this series was Ulrika Jonsson, with Terry Christian second.

This was the first series of Celebrity Big Brother to air since the racism controversy of 2007, during series 5, although Channel 4’s sister channel E4 aired a similar spin-off in 2008, entitled Big Brother: Celebrity Hijack.

This series was the least watched Celebrity Big Brother series, averaging 3.3 million viewers; at the time of transmission, it was also the least watched series of any Big Brother in the UK (excluding spin-offs) until the tenth non-celebrity series pulled in 2.5 million. Despite the low viewership, the launch show was the most watched programme of 2009 on Channel 4, raking in 6 million viewers.

Ulrika and Coolio took part in Ultimate Big Brother in 2010. Coolio was removed within the first few days and Ulrika finished seventh on the final night.