Britain's Best Brain is a television programme running in the United Kingdom on Channel 5 and saw ordinary members of the public undertake various tasks, all scientifically designed to test different parts of the brain. The show ran every Wednesday and was aired from 28 October to 16 December 2009. The winner, crowned 'Britain's Best Brain 2009', was Matt Clancy, a 29 year-old marketing consultant from London.

The show was hosted by former Live & Kicking presenters Jamie Theakston and Zoë Ball.

A free to play browser game was launched on 3 October 2009 and was commissioned by Tiger Aspect Productions and developed by Fish in a bottle.