The Arena Football League (AFL) can refer to one of three successive professional indoor American football leagues in the United States. The first of these was founded in 1986, and played its first official games in the 1987 season, running for 22 consecutive seasons until going bankrupt following the 2008 season. The second league, consisting largely of teams from the first AFL and arenafootball2, purchased the first league's assets out of bankruptcy and resumed play in 2010 as a continuation of the first AFL; this second AFL ran for ten further seasons, before again going bankrupt following the 2019 season. The third and current AFL, which is not directly connected to the previous two iterations of the league but claiming their histories and trademarks, launched in 2024.

Arena football is a variety of eight-man indoor gridiron football. The game is played indoors on a smaller field than American or Canadian football, designed to fit in the same surface area as a standard North American ice hockey rink, resulting in a faster and higher-scoring game that can be played on the floors of indoor arenas. The sport was invented in 1981, and patented in 1987, by Jim Foster, a former executive of the National Football League and the United States Football League. The name is trademarked by Gridiron Enterprises and had a proprietary format until its patent expired in 2007.