The English Football League One, often called League One, is England's third-tier professional football division, officially rebranded in the 2004–05 season. Contested by 24 clubs, it's a crucial part of the English football pyramid, where teams battle for promotion to the EFL Championship and strive to avoid relegation to League Two.

Uniquely, League One holds the distinction of being the most-watched third-tier domestic sports league in the world, drawing an impressive average of 10,613 spectators per game during the 2022–23 season. This popularity is further highlighted by a record single-game attendance of 46,039 in 2018–19. The division frequently features historically significant clubs, including several former Premier League teams like Bolton Wanderers and Cardiff City, with Burton Albion currently holding the longest tenure in the league.