The National Basketball League was a professional basketball league in the United States from 1937 to 1949. The NBL started with 13 previously independent teams in 1937-38. The league was created by three corporations General Electric, Firestone and Goodyear. It was comprised primarily of teams in small Great Lakes towns and by corporate teams. The NBL lasted 12 years before merging with the three-year-old Basketball Association of America in 1949, with the resulting combination being renamed the National Basketball Association.

Five current NBA teams trace their history back to the NBL. Three teams joined the NBA in 1948: the Los Angeles Lakers (then the Minneapolis Lakers), the Sacramento Kings (then the Rochester Royals), and the Detroit Pistons (then the Fort Wayne Pistons). Two more teams joined the NBA in 1949: the Atlanta Hawks (then the Tri-Cities Blackhawks, the three cities being Moline, Illinois, Rock Island, Illinois, and Davenport, Iowa) and the Philadelphia 76ers (then the Syracuse Nationals, or "Nats" for short).

Also still surviving are the Akron Goodyear Wingfoots, the initial NBL Champion in 1938. The Wingfoots suspended operations for World War II and were not included in the NBL/BAA merger. Instead, they remained in the National Industrial Basketball League (NIBL), which in 1961 became the National AAU Basketball League (NABL). The Wingfoots are still an AAU Elite team in the NABL.

A total of 10 established NBL teams joined the Basketball Association of America/National Basketball Association. In addition to the Lakers, Pistons, Royals/Kings, Blackhawks/Hawks and Nationals/76ers, the Anderson Packers, Denver Nuggets, Indianapolis Kautskys (as the Indianapolis Jets), Sheboygan Redskins and Waterloo Hawks played in the BAA/NBA. The NBL had also created an expansion team for the 1949-50 NBL season (the Indianapolis Olympians) when NBL and BAA merged; this team also joined the NBA.