Flag football is a variant of gridiron football (American football or Canadian football depending on location) where, instead of tackling players to the ground, the defensive team must remove a flag or flag belt from the ball carrier ("deflagging") to end a down. In flag football, contact is limited between players. The sport has a strong amateur following with several national and international competitions each year sponsored by various associations but is most popularly played in America where it was invented. The international governing body for the sport is the International Federation of American Football (IFAF) with the International Woman's Flag Football Association (IWFFA) governing the women's game.

Flag football will be a discretionary event for the 2028 Summer Olympics in Los Angeles, the first time any gridiron football code has been a full part of an Olympic programme.

The best available records to date point to the early 1940s during World War II as the sport's starting point. The game began as a recreational sport created for American military personnel to help them stay fit but was designed in a way that would help prevent them from becoming injured during wartime. At the time it was called "Touch and Tail football", which then became "flag football" after the war ended.

The first known recorded history of flag football can be traced to Fort Meade, Maryland, USA, which is now generally accepted as the sport's birthplace. The first national flag football organization, the National Touch Football League (NTFL), was formed in the 1960s in St. Louis, Missouri. Since 1971, the league has had a national championship game.

Arizona teachers Porter Wilson and Norman Adams invented flag-a-tag belts and flags which are the template for the flags used in the game today.

The specific rules of flag football vary widely by league, though all share in common their replication of the rules of traditional American football with tackling replaced by flag-pulling.

Traditional American football rules are often eliminated or modified to reflect the more recreational nature of the game, the desire to avoid physical contact and injury, and the generally smaller number of participating players per side.

In a standard game of flag football, the match is played in two halves. Time length is determined by the league being played. The clock only stops for injuries, half-time and timeouts. Most leagues have 10 players per team, 5 on offense and 5 on defence, there is no punting team for flag football.