The National Basketball League (NBL) Championship was the final series for the NBL and the conclusion of its postseason.
The championship series were played in varying best-of-three or best-of-five formats.
However, due to fewer teams in the league caused by World War II, the NBL was not separated into divisions between 1940–41 and 1943–44, therefore the playoffs included the top four teams in the single-division league.
Home court advantage was determined by better overall record heading into the championship series.
Three teams are tied with the most NBL championships at two each – the Akron Firestone Non-Skids (1939, 1940), Oshkosh All-Stars (1941, 1942), and Fort Wayne Zollner Pistons (1944, 1945).