The National Basketball League (NBL) was a professional basketball league in the United States, established in 1937. After the 1948–49 season, its twelfth, it merged with the Basketball Association of America (BAA) to create the National Basketball Association (NBA). Five current NBA teams trace their history back to the NBL: the Atlanta Hawks, the Detroit Pistons, the Los Angeles Lakers, the Philadelphia 76ers, and the Sacramento Kings.

The NBL was initially founded as the Midwest Basketball Conference (MBC) in 1935. It changed its name in 1937 in an attempt to attract a larger audience. The league was created by three corporations: General Electric, Firestone and Goodyear. It was primarily made up of Great Lakes area small-market and corporate teams.

The league began rather informally. Scheduling was left to the discretion of each of the teams, as long as the team played at least ten games and four of them were on the road. Games played increased yearly as the popularity of professional basketball and the NBL grew in America. Games consisted either of four ten-minute quarters or three fifteen-minute periods. The choice was made by the home team. Some of the teams were independent, while others were owned by companies that also found jobs for their players.

Chicago newspaper sports editor Leo Fischer acted as president of the NBL from 1940–44.

In 1946, the Basketball Association of America (BAA) incorporated resulting in a three-year battle with the NBL to win both players and fans. The BAA played its games in larger cities and venues. However, NBL tended to have the bigger stars.^[1] NBL teams dominated the World Professional Basketball Tournament, an annual invitational tournament held in Chicago and sponsored by the Chicago Herald American. NBL teams won seven out of ten editions of the tournament.

On August 3, 1949, representatives from the 12-year-old NBL and 3 year old BAA met at the BAA offices in New York's Empire State Building to finalize a merger. Maurice Podoloff was elected head of the new league. The new National Basketball Association (NBA) was made up of 17 teams that represented both small towns and large cities across the country. The NBA claims the BAA's history as its own and considers the 1949 deal as an expansion, not a merger. For example, at NBA History online, its table of one-line "NBA Season Recaps" begins 1946–47 without comment.^[2] It celebrated "NBA at 50" in 1996, with announcement of its 50 Greatest Players among other things.^[3][4]

The NBA does not recognize NBL records and statistics except under certain circumstances.^[4] As such, the records and statistics of the BAA and NBL prior to the merger in 1949 are considered in official NBA history only if a player, coach, or team participated in the newly formed NBA after 1949 for one or more seasons.^[5][6]

The history of the NBL falls into three eras, each contributing significantly to the growth of professional basketball and the emergence of the NBA. The first dynasty centered on the Oshkosh All-Stars and their center Leroy "Cowboy" Edwards. The middle years saw the emergence of the Fort Wayne Zollner Pistons, who were later instrumental in the survival of the NBA during its infancy. The final period of note during the NBL's existence centered on George Mikan and the emergence of the big man in basketball.^[7]

The NBL contributed significantly to the foundation of the NBA, but it also had major accomplishments in other areas, most notably in offering opportunities for African-American players. In the 1942–43 season, with many players in the armed forces, two NBL clubs, the Toledo Jim White Chevrolets and the Chicago Studebakers, filled their rosters by signing African-Americans—five years before Jackie Robinson would break baseball's color barrier with the Brooklyn Dodgers. Neither team fared well. Toledo signed several black players to start the season, including Bill Jones, who had starred at the University of Toledo, but the team lost its first four games and folded due to financial difficulties. Chicago stocked its roster with several members of the Harlem Globetrotters, who worked during the week at the Studebaker plant, but it also folded after compiling an 8–15 record.

Five current NBA teams trace their history back to the NBL. Three teams joined the BAA in 1948: the Minneapolis Lakers (now the Los Angeles Lakers), the Rochester Royals (now the Sacramento Kings), and the Fort Wayne Zollner Pistons (now the Detroit Pistons). Two more teams were part of the merger that created the NBA in 1949: the Buffalo Bisons/Tri-Cities Blackhawks (now the Atlanta Hawks), and the Syracuse Nationals (now the Philadelphia 76ers).

Five former NBA teams also trace their history back to the NBL: the Anderson Packers, Denver Nuggets, Indianapolis Jets (as the Kautskys), Sheboygan Red Skins and Waterloo Hawks played in the NBL/BAA/NBA. The Jets played in the BAA for the 1948–49 season only; the remaining teams for the 1949–50 season only. Anderson, Sheboygan, and Waterloo joined the National Professional Basketball League in 1950.

The NBL also created the Indianapolis Olympians for the 1949–50 NBL season. When the NBL and BAA merged, this team joined the NBA without playing a single NBL game.

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.

^[8] Note: # denotes a team currently playing in the NBA. ^{[9] [10]}

• List of NBL champions
• List of NBL season scoring leaders
• List of NBL career scoring leaders
• List of NBL Most Valuable Players
• List of NBL Rookies of the Year
• List of NBL Coaches of the Year