The 2009 Avon Tyres British GT season was the 17th season of the British GT Championship. The season began at Oulton Park's Easter Monday meeting and finished on 20 September at Brands Hatch after 14 races. 2009 saw the debut of the new Supersport class. Twins David and Godfrey Jones won the GT3 title during the final race of the season. Jody Firth sealed the GT4 title, while Phil Keen and Marcus Clutton won the Supersports Class.