The decision announced by the team on Tuesday means the Big Three of Allen, Paul Pierce and Kevin Garnett will be together for one more season. Garnett has one year left on his contract and Pierce has three years remaining.
Allen has spent four seasons as the Celtics shooting guard after being traded from Seattle. In 2007-08, the first season of the Big Three, the Celtics won their 17th NBA title.
In 15 NBA seasons, Allen has 22,286 points, 24th in league history. Last season, he set the NBA record for 3-point field goals made in a career at 2,612.