The 2011 Cooper Tires British Formula 3 International Series was the 61st British Formula Three Championship season. The season began on 16 April at Monza in Italy and ended on 9 October at Silverstone after 30 races held at ten meetings. Of those meetings, six were held in the United Kingdom, with overseas rounds at Monza, the Nürburgring in Germany, Paul Ricard in France, and Spa in Belgium.
Brazilian driver Felipe Nasr dominated the series, winning seven races and recording 16 top three finishes over the first eight rounds of the series, putting him 123 points ahead of Nasr's Carlin Motorsport team mate, Danish driver Kevin Magnussen, giving him an unassailable lead in the championship with two rounds still in hand.
A number of changes were announced for the season, with pit-stops set to be introduced in the third race of each round, but this plan was later abandoned in July 2011. The championship's class system – Championship and National – was also renamed to the International and Rookie Championships. The Rookie winner will receive a fully paid entry to the 2012 International Championship.