Barra brava (lit. 'fierce group') is the name of organized supporters' groups of football teams in Hispanic America that provides fanatical support to their clubs in stadiums and provoke violence against rival fans as well as against the police.

Actions such as welcome the team when it goes out to the pitch (by the use of pyrotechnics, throwing confetti and balloons, and displaying giant flags); waving and displaying of flags, banners and umbrellas; and the coordination of chants during the whole match, are characteristic of their fervent behavior, whose purpose is to encourage their team while intimidating referees and rival fans and players, for which they also provoke violence.

They also look to attack rival fans or defend their team' spectators from rival attacks (especially in away matches, where normally they are outnumbered by home fans) and police repression.

These groups originated in Argentina in the 1950s and spread throughout the rest of Latin America.^{[citation needed]} They are similar to hooligan firms (from United Kingdom), torcidas organizadas (from Brazil), and ultras (originally from Italy but spread to the most part of Europe and Asia, Australia, and North Africa).

In Rioplatense Spanish slang, barra is a term used for 'group of people' (usually friends who share common interests and tend to frequent the same places). During the 1920s in Argentine football matches, some fan groups (called barras) stood out among the public for their fervent behavior, which sometimes included violent actions. These groups were irregular, and their violence arose spontaneously sometimes due to frustration caused by bad results of their team or as a way to influence the matches by intimidating referees and rival players with insults, throwing objects and occasionally entering onto the pitch to assault them. Sometimes they also attacked rival fans who used the same methods against their team. At the end of this decade, a few newspapers described one of this groups as a barra "brava" (Spanish for fierce), appearing the words barra brava together for the first time, but not yet like a term.

For example, one of those groups appeared in 1927, supported San Lorenzo de Almagro and was named La barra de la goma ("The group of the rubber") by the press. The nickname comes from the use of rubber taken from bicycle inner tubes, filled with sand and tied with wire at the ends, to attack opposing fans. They sometimes also threw objects at opposing players to annoy them when they were supposed to intervene in the match.

These barras became a traditional part of the Argentine football crowds and evolved until each team had a main one, which in the 1950s began to be considered by club directors as a fundamental part of the fanbase due to their ability to intimidate and repel or respond to attacks from rival fans, especially in away matches. That's how in some occasions they started to receive tickets or paid rides to the stadiums. Argentine journalist Amílcar Romero stated that, before the appearance of such groups, when a team played away, they were intimidated by home fans. Barras bravas were a response to this pressure, so each club started to have its own one, partially financed by the club leadership. Access to benefits (as tickets and travel) was controlled by group's leaders, and to gain prestige, a member had to be violent.

In Argentine football it was customary that, if you played away, they put pressure on you inexorably. Although it was not about barras bravas as we know them today. Home fans put pressure on you, and the police, if they weren't looking the other way, put pressure on you too. That had to be compensated with a theory that in the next decade (the 1950s) was rife: to every operating group with a "mystical" ability to produce violence, the only way to counter it is with another minority group, with as much or more "mystique" to produce violence.