The Boston Celtics went 11-1 in the NBA Finals during thirteen seasons (1956-1957 to 1968-1969). The Boston Celtics won the NBA Finals 8 years in a row during the 1958-59 to 1965-66 NBA seasons.[2] The Boston Celtics and Los Angeles Lakers made up 19 of 26 possible NBA appearances during thirteen seasons (1956-1957 to 1968-1969).