The Boston Celtics is a basketball team in the NBA. The Boston Celtics is one of the most succesful teams of all-time. They have the most championships in the whole NBA at 17. The current head coach is Brad Stevens, who began his tenure in 2013. The Celtics play their home games at the TD Garden, which they share with the National Hockey League Boston Bruins. The franchise's 17 championships are the most of any NBA franchise, and account for 24.6 percent of all NBA championships since the league's founding in 1946.