Mass unrest by the Primeiro Comando da Capital begins in São Paulo (Brazil), leaving at least 150 dead.

The 2006 São Paulo violence outbreak began on the night of May 12, 2006 in São Paulo, Brazil, the largest city in South America. It was among the worst outbreaks of violence in recorded Brazilian history and was directed against security forces and a few civilian targets. By May 14 the attacks had spread to other Brazilian states including Paraná, Mato Grosso do Sul, Minas Gerais and Bahia.

The Primeiro Comando da Capital, also referred to as 15.3.3 or simply as Partido ("Party"), is a Brazilian organized crime syndicate. According to a 2023 The Economist report, the PCC is Latin America's biggest drug gang, with a membership of 40,000 lifetime members plus 60,000 "contractors". Its name refers to the São Paulo state capital, the city of São Paulo.

São Paulo is the capital city of the state of São Paulo, as well as the most populous city in Brazil, the Americas, and both the Western and Southern Hemispheres. Listed by the Globalization and World Cities Research Network (GaWC) as an alpha global city, it exerts substantial international influence in commerce, finance, arts, and entertainment. It is the largest urban area by population outside Asia and the most populous Portuguese-speaking city in the world. The city's name honors Paul the Apostle and people from the city are known as paulistanos. The city's Latin motto is Non ducor, duco, which translates as "I am not led, I lead".