Peronism, also called justicialism, is an Argentine political movement based on the ideas and legacy of Argentine ruler Juan Perón (1895–1974). It has been an influential movement in 20th and 21st century Argentine politics. Since 1946, Peronists have won 10 out of the 13 presidential elections in which they have been allowed to run. The main Peronist party is the Justicialist Party. The policies of Peronist presidents have differed greatly, but the general ideology has been described as "a vague blend of nationalism and labourism" or populism.

Perón became Argentina's labour secretary after participating in the 1943 military coup and was elected president of Argentina in 1946. He introduced social programs that benefited the working class, supported labor unions and called for additional involvement of the state in the economy. In addition, he helped industrialists. Perón was hugely popular and gained even more admiration through his wife Eva, who championed for the rights of migrant workers and was beloved by the people.

Eva was so beloved that, in 1949, Juan Perón formed the Female Peronist Party, a new wing within his own party under her leadership. Due to rising inflation and other economic problems and political repression, the military overthrew Perón in 1955. The Peronist party was banned and it was not until 1973 that open elections were held again in which Perón was re-elected president.

Perón died the next year; his widow and vice president Isabel took over the presidency.

Perón's death left an intense power vacuum and the military promptly overthrew Isabel in 1976. Following the return to democracy in 1983 Peronist candidates dominated the presidency. In 37 years of democracy, Peronists held the presidency for 24 years.

Carlos Menem was elected in 1989 and served for two consecutive terms over ten years. His main focus was the privatization of state run enterprises, the adoption of free-market policies and good international relations with the United States. After the De La Rúa administration collapsed, two interim Peronist leaders took over: Adolfo Rodríguez Saá and later Eduardo Duhalde. Left-wing Peronist Néstor Kirchner, elected in 2003, served for only one term, while his wife, Cristina Fernández de Kirchner, served two (having been elected in 2007 and re-elected in 2011), and is, since 2019, the current vice president with Alberto Fernández as president.

Peronism is considered a paternalistic ideology. Some scholars evaluate Peronism as a mixture of 'militant laborism' and 'traditional conservatism'. However, supporters of Peronism see it as socially progressive.