"Hooliganism" is the term used broadly to describe disorderly, aggressive and often violent behaviour perpetrated by spectators at sporting events. In the UK, hooliganism is almost exclusively confined to football.

Disorderly behaviour has been common amongst football supporters since the birth of the sport, but it is only really since the 1960s that it began to be perceived as a serious problem.

In the 1980s, however, hooliganism became indelibly associated with English football supporters, following a series of major disturbances at home and abroad, which resulted in numerous deaths. Vigorous efforts by governments and the police since then have done much to reduce the scale of hooliganism.

However, it still persists, albeit in new forms. Today, in contrast to the more or less spontaneous upsurges of violence of the past, gangs of rival fans will frequently arrange to meet at specific locations, using mobile phones or the Internet, before and after matches to fight.

Furthermore, while England has the worst international reputation for hooliganism, a number of other countries have similar and growing problems. Today, the highest profile hooliganism problems tend to occur in relation to international matches and events.

In all these countries, some gangs of hooligans share other characteristics, interests and beliefs that incline them towards violent conduct, including links to far-right and racist organisations. Others, however, are apolitical, and are simply composed of men who enjoy fighting.

The term "hooligan" has a disputed derivation, but it is generally accepted to have begun to appear in London police reports in 1898 in relation to violent street gangs.