The Constitutionalist Revolution of 1932 (sometimes also referred to as Paulista War or Brazilian Civil War) is the name given to the uprising of the population of the Brazilian state of So Paulo against the Brazilian Revolution of 1930 when Getlio Vargas assumed the nation's Presidency; Vargas was supported by the people, the military and the political elites of Minas Gerais, Rio Grande do Sul and Paraba. The movement grew out of local resentment from the fact that Vargas ruled by decree, unbound by a Constitution, in a provisional government. The 1930 Revolution also affected So Paulo by eroding the autonomy that states enjoyed during the term of the 1891 Constitution and preventing the inauguration of the governor of So Paulo Jlio Prestes in the Presidency of the Republic, while simultaneously overthrowing President Washington Lus, who was governor of So Paulo from 1920 to 1924. These events marked the end of the First Republic. Vargas appointed a northeasterner as governor of So Paulo.

The Revolution's main goal was to press the provisional government headed by Getlio Vargas to adopt and then abide by a new Constitution, since the elected President Prestes was kept from taking office. However, as the movement developed and resentment against President Vargas and his revolutionary government grew deeper, it came to advocate the overthrow of the Federal Government, and it was even speculated that one of the Revolutionaries' goals was the secession of So Paulo from the Brazilian federation. However, it is noted that the separatist scenario was used as a guerrilla tactic by the Federal Government to turn the population of the rest of the country against the state of So Paulo, broadcasting the alleged separatist notion throughout the country. There is no evidence that the movement's commanders sought separatism.

The uprising commenced on 9 July 1932, after four protesting students were killed by government troops on 23 May 1932. On the wake of their deaths, a movement called MMDC (from the initials of the names of each of the four students killed, Martins, Miragaia, Drusio and Camargo) started. A fifth victim, Alvarenga, was also shot that night, but died months later.

In a few months, the state of So Paulo rebelled against the federal government. Counting on the solidarity of the political elites of two other powerful states, (Minas Gerais and Rio Grande do Sul), the politicians from So Paulo expected a quick war. However, that solidarity was never translated into actual support, and the So Paulo revolt was militarily crushed on October 2, 1932.

In total, there were 87 days of fighting (July 9 to October 4, 1932with the last two days after the surrender of So Paulo), with a balance of 934 official deaths, though non-official estimates report up to 2,200 dead, and many cities in the state of So Paulo suffered damage due to fighting.

In spite of its military defeat, some of the movement's main demands were finally granted by Vargas afterwards: the appointment of a non-military state Governor, the election of a Constituent Assembly and, finally, the enactment of a new Constitution in 1934. However that Constitution was short-lived, as in 1937, amidst growing extremism on the left and right wings of the political spectrum, Vargas closed the National Congress and enacted another Constitution, which established an regime called Estado Novo.

July 9 marks the beginning of the Revolution of 1932, and is a holiday and the most important civic date of the state of So Paulo. The paulistas (as the inhabitants of So Paulo are known) consider the Revolution of 1932 as the greatest movement of its civic history. It was the first major revolt against the government of Getlio Vargas and the last major armed conflict occurring in the history of Brazil.

São Paulo (Portuguese pronunciation: [sɐ̃w ˈpawlu] (listen)) is one of the 26 states of the Federative Republic of Brazil and is named after Saint Paul of Tarsus. A major industrial complex, the state has 21.9% of the Brazilian population and is responsible for 33.9% of Brazil's GDP. São Paulo also has the second-highest Human Development Index (HDI) and GDP per capita, the fourth-lowest infant mortality rate, the third-highest life expectancy, and the third-lowest rate of illiteracy among the federative units of Brazil. São Paulo alone is wealthier than Argentina, Uruguay, Paraguay, and Bolivia combined. São Paulo is also the world's twenty-eighth-most populous sub-national entity and the most populous sub-national entity in the Americas.

With more than 46 million inhabitants in 2019, São Paulo is the most populous Brazilian state, the most populous national subdivision in the Americas, and the third most populous political unit of South America, surpassed only by the rest of the Brazilian Federation and Colombia. The local population is one of the most diverse in the country and descended mostly from Italians, who began immigrating to the country in the late 19th century; of the Portuguese, who colonized Brazil and installed the first European settlements in the region; indigenous peoples, many distinct ethnic groups; Africans, who were brought from Africa as slaves in the colonial era and migrants from other regions of the country. In addition, Arabs, Germans, Spanish, Japanese, Chinese, and Greeks also are present in the ethnic composition of the local population.

The area that today corresponds to the state territory was already inhabited by indigenous peoples from approximately 12,000 BC. In the early 16th century, the coast of the region was visited by Portuguese and Spanish explorers and navigators. In 1532 Martim Afonso de Sousa would establish the first Portuguese permanent settlement in the Americas—the village of São Vicente, in the Baixada Santista. In the 17th century, the paulistas bandeirantes intensified the exploration of the colony's interior, which eventually expanded the territorial domain of Portugal and the Portuguese Empire in South America. In the 18th century, after the establishment of the Province of São Paulo, the region began to gain political weight. After independence in 1820, São Paulo began to become a major agricultural producer (mainly coffee) in the newly constituted Empire of Brazil, which ultimately created a rich regional rural oligarchy, which would switch on the command of the Brazilian government with Minas Gerais's elites during the early republican period in the 1880s. Under the Vargas Era, the state was one of the first to initiate a process of industrialization and its population became one of the most urban of the federation.

The city of São Paulo, the homonymous state capital, is ranked as the world's 12th largest city and its metropolitan area, with 20 million inhabitants, is the 9th largest in the world and first in the Americas. Regions near the city of São Paulo are also metropolitan areas, such as Campinas, Santos, Sorocaba and São José dos Campos. The total population of these areas coupled with the state capital—the so-called "Expanded Metropolitan Complex of São Paulo"—exceeds 30 million inhabitants, i.e. approximately 75 percent of the population of São Paulo statewide, the first macro-metropolis in the southern hemisphere, joining 65 municipalities that together are home to 12 percent of the Brazilian population.