the national basketball association (nba) is the world's top men's professional basketball league. it is one of the major professional sports leagues of north america. there are 30 teams in the league. 29 are in the united states and 1 is in canada. it is a member of usa basketball (usab). the nba is one of the 4 major north american professional sports leagues. nba players are the world's best paid athletes. they have the highest average annual salary.