The Belgrade Football Subassociation, commonly known by its initials, BLP (Serbo-Croato-Slovenian: Beogradski loptački podsavez / Београдски лоптачки подсавез - БЛП) was one of the regional football governing bodies under the tutorial of the Football Association of Yugoslavia. It was formed on 12 March 1920, and included the clubs from the geographical territories of Vojvodina, Central Serbia, Old Serbia (Kosovo) and South Serbia (Macedonia). The increase of number of clubs made that progressively other subassociations become formed by separating them from Belgrade's one. By 1932 its territory included beside Belgrade metropolitan area only the districts of Kolubara, Braničevo, Podunavlje and Jasenica-Kosmaj.[1]
Its main role was to organise and control the league competition which consisted in interconnected leagues in a hierarchical format with promotion and relegation between leagues at different levels.
At the top of the hierarchy was the First Division of the BLP (1. razred BLP / 1. разред БПЛ), often known simply as Belgrade Football Subassociation League and the winner had direct access to the Yugoslav Championship while the second placed had to play a qualifying round. The Second and Third Divisions were divided in groups.[2]