List of National Football League champions

The National Football League champions, prior to the merger between the National Football League (NFL) and American Football League (AFL) in 1970, were determined by two different systems. The National Football League was established on September 17, 1920, as the American Professional Football Association (APFA). The APFA changed its name in 1922 to the National Football League, which it has retained ever since.

From 1921 to 1931, the APFA/NFL determined its champion by overall win–loss record, with no playoff games; ties were not counted in the winning percentage total. The APFA did not keep records of the 1920 season; they declared the Akron Pros, who finished the season with an 8–0–3 (8 wins, 0 losses, 3 ties) record, as the league's first champions, by a vote of the owners, with the Buffalo-All Americans and Decatur Staleys also claiming the title. According to modern-tie breaking rules, the Buffalo All-Americans tied Akron for the championship. The Canton Bulldogs won two straight championships from 1922 to 1923, and the Green Bay Packers won three in a row from 1929 to 1931.

There also has been controversy over the championshipships of the 1921 APFA season and the 1925 NFL season, with the Buffalo All-Americans laying claim to another championship in an incident known as the "Staley Swindle" and the Pottsville Maroons being stripped of their championship in 1925 for playing an exhibition game against college football powerhouse Notre Dame's famed Four Horsemen, leading to a last minute field goal victory for the Maroons, stunning the crowd and nation, and also put the NFL ahead of college football for the first time ever. These three disputed championships contributed to the beginning of the NFL's rich history.

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