The American Poolplayers Association (APA) was founded in 1981 by professional pool players Terry Bell and Larry Hubbart, although with roots dating back to the National Pool League (NPL), founded in 1979. The APA conducts a system of franchised-based local amateur leagues of pool (pocket billiards) competition, including both eight-ball and nine-ball, with a unified APA ruleset. The organization, which has affiliates in Canada and Japan, hosts regional tournaments the winners of which qualify for the annual APA international tournament played in Las Vegas, Nevada. The organization claims to be the world's largest pool league, and cites an individual membership roster of approximately 265,000 players.
The APA employs a handicapping system called "the Equalizer" that allows players of all ability to compete on an equal basis. These systems are explained below for both nine-ball and eight-ball. The normal APA team matches consist of 5 race-format one-on-one competitions (similar to matches in the USA Pool League, and very different from the round-robin format used by the BCA Pool League and VNEA). However, APA organizers at the local level often set up non-team tournaments, doubles play, and other formats, and the annual championships feature both individual and team play.