The American League (or AL) is one of the two leagues that make up Major League Baseball (MLB). The other is the National League (or NL). The American League is made up of 15 teams. At the end of each season, five of these teams go to the "post-season" where one will win the American League championship. The champions of the American League plays against the champions of the National League in the World Series. The team that wins the World Series is the champion of Major League Baseball. Teams in the American league usually play against other teams in the American league, except for a few games a year when they play National league teams. There are 3 Divisions of the American League: AL East, AL Central, and AL West.