The X-League (Xリーグ) is the top-level professional gridiron football league in Japan.

It was founded in 1971 as the Japan American Football League and organized the first X Bowl in 1987.

The league is divided into four divisions (X1 Super, X1 Area, X2, and X3) with promotion and relegation between them.

Game rules are based on those of the NCAA college division in the United States, with the exception of the length of quarters, which are 12 minutes instead of 15 during the first stage of the season.

The Japanese national team, which has won the first and second editions of the American Football World Cup and was runner-up, finishing second to the American team, in the 2007 installment of the tournament, was made up almost entirely of players from this league.

There are two spring tournaments as well which are used by teams to ready themselves and evaluate new players before the fall season.

At the end of the X1 Super season, the top four teams in each division head into the quarterfinals then the semifinals.

The two semifinal winners would meet for the league championship in the Japan X Bowl held at the Tokyo Dome.