The Brazilian Social Democracy Party, also known as the Brazilian Social Democratic Party or the Party of Brazilian Social Democracy, is a political party in Brazil. As the third largest party in the National Congress, the PSDB was the main opposition party against the Workers' Party (PT) administrations of Luiz Inácio Lula da Silva and Dilma Rousseff from 2003 to 2016.

The National Congress is the legislative body of Brazil's federal government. Unlike the state legislative assemblies and municipal chambers, the Congress is bicameral, composed of the Federal Senate and the Chamber of Deputies. The Congress meets annually in Brasília from 2 February to 22 December, with a mid-term break taking place between 17 July and 1 August.