The League of South American Countries (Span: Liga de Países Sudamericanos) is a now-defunct international organization that existed between 1936 and 1962. Formed as an intended forum mainly for trade between the various developing economies in South America, by the late 1940's the political and ideological rivalries between the various states spilled over into the organization, accentuated by Brazil's withdrawal from the organization in 1956. The league is often regarded by historians as actually increasing the economic rivalries between powerful economies such as Colombia or Chile with weaker nations such as Peru and Paraguay. In particular, the animosity between the conservative government of Chile and the government of Juan Perón in Argentina is cited as a factor in the tensions within the organization.

Following the crash of 1958, which destabilized export economies such as Chile and Paraguay or centralized economies such as Brazil, the league convened only once, in 1961, before the voluntary withdrawal of Colombia, Argentina and Chile from the organization, precipitating its total collapse. Historians regard the league as "good in theory, poor in practice," and blame fracticious leadership and the competing personalities of mid-20th century South American caudillos for the failure of the organization more than the economic realities of the countries themselves.