The National Basketball Association (NBA) is a professional basketball league in North America. The league is composed of 30 teams (29 in the United States and 1 in Canada) and is one of the major professional sports leagues in the United States and Canada. It is the premier men's professional basketball league in the world.The league was founded in New York City on June 6, 1946, as the Basketball Association of America (BAA). It changed its name to the National Basketball Association on August 3, 1949, after merging with the competing National Basketball League (NBL). In 1976, the NBA and the American Basketball Association (ABA) merged, adding four franchises to the NBA. The NBA's regular season runs from October to April, with each team playing 82 games. The league's playoff tournament extends into June. As of 2020, NBA players are the world's best paid athletes by average annual salary per player.The NBA is an active member of USA Basketball (USAB), which is recognized by the FIBA (International Basketball Federation) as the national governing body for basketball in the United States. The league's several international as well as individual team offices are directed out of its head offices in Midtown Manhattan, while its NBA Entertainment and NBA TV studios are directed out of offices located in Secaucus, New Jersey. In North America, the NBA is the third wealthiest professional sport league after the National Football League (NFL) and Major League Baseball (MLB) by revenue, and among the top four in the world.The Boston Celtics and the Los Angeles Lakers are tied with the most NBA championships at 17 each. The Golden State Warriors are the defending league champions, as they defeated the Boston Celtics 42 in the 2022 NBA Finals.

The Basketball Association of America (BAA) was a professional basketball league in North America, founded in 1946. Following its third season, 1948–49, the BAA absorbed most of National Basketball League (NBL) and rebranded as the National Basketball Association (NBA).The Philadelphia Warriors won the inaugural BAA championship in 1947, followed by the Baltimore Bullets and the Minneapolis Lakers in 1948 and 1949, respectively. Six teams from the BAA remain in operation in the NBA as of the 2017–18 season, three that co-founded the league in 1946 and three that joined it from the NBL in 1948 (below). The inaugural BAA season began with 11 teams, of which four dropped out before the second season. One ABL team joined to provide 8 teams for 1947–48 and four NBL teams joined to provide 12 for 1948–49. The records and statistics of the BAA and NBL prior to the merger in 1949 are considered in official NBA history only if a player, coach or team participated in the newly formed NBA after 1949 for one or more seasons.The NBA generally claims the BAA's history as its own. For example, at NBA History online its table of one-line "NBA Season Recaps" begins 1946–47 without comment. It celebrated "NBA at 50" in 1996, with announcement of its 50 Greatest Players among other things.