Major League Soccer (MLS) is a North American professional league for soccer clubs. MLS represents the top tier of the American Soccer Pyramid. MLS is comprised of 14 clubs, although the league continues to expand to 15 clubs by 2009. Seasons run from Late March or Early April to November, with teams playing 30 games each.

A total of 16 clubs have competed in Major League Soccer, but only six have won the MLS Cup: D.C. United, Los Angeles Galaxy, San Jose Earthquakes, Chicago Fire, Kansas City Wizards, and Houston Dynamo. The current Major League Soccer champions are the Houston Dynamo, who won their second title in the 2007 season.