United States soccer league system in the context of "National Women's Soccer League"

Major League Soccer (MLS) is a professional soccer league in North America and the highest level of the United States soccer league system. It comprises 30 teams, with 27 in the United States and 3 in Canada, and is sanctioned by the United States Soccer Federation. MLS is one of the major professional sports leagues in the United States and Canada. The league is headquartered in Midtown Manhattan.

The predecessor of MLS was the North American Soccer League (NASL), which existed from 1968 until 1984. MLS was founded in 1993 as part of the United States' successful bid to host the 1994 FIFA World Cup. The inaugural season took place in 1996 with ten teams. MLS experienced financial and operational struggles in its first few years, losing millions of dollars and folding two teams in 2002. Since then, developments such as the proliferation of soccer-specific stadiums around the league, the implementation of the Designated Player Rule allowing teams to sign star players such as David Beckham and Lionel Messi, and national TV contracts have made MLS profitable.

MLS Next Pro (MLSNP) is a men's professional soccer league in the United States and Canada that is affiliated with Major League Soccer (MLS). It launched in 2022 with 21 teams and now comprises 27 reserve sides of MLS clubs and two independent clubs (Carolina Core FC and Chattanooga FC). MLS Next Pro is classified as part of the third tier of the United States soccer league system.

As of the 2025–26 season, 27 of the 30 MLS teams held affiliations with an MLS Next Pro team, with only the CF Montréal, D.C. United, and San Diego FC having no such franchise affiliation.