Tendencia Revolucionaria (lit. Revolutionary Tendency), Tendencia Revolucionaria Peronista, or simply la Tendencia or revolutionary Peronism, was the name given in Argentina to a current of Peronism grouped around the guerrilla organisations FAR, FAP, Montoneros and the Juventud Peronista. Formed progressively in the 1960s and 1970s, and so called at the beginning of 1972, it was made up of various organisations that adopted a combative and revolutionary stance, in which Peronism was conceived as a form of Christian socialism, adapted to the situation in Argentina (socialismo nacional), as defined by Juan Perón himself. The Tendencia was supported and promoted by Perón, during the final stage of his exile, because of its ability to combat the dictatorship that called itself the Argentine Revolution. It had a great influence in the Peronist Resistance (1955-1973) and the first stage of Third Peronism, when Héctor J. Cámpora was elected President of the Nation on 11 March 1973.

The Revolutionary Tendency was made up of Montoneros-FAR as the core organisation and a group of non-military organisations, namely: Juventud Peronista Regionales (JP), Agrupación Evita de la Rama Femenina del Movimiento Peronista (AE), Juventud Universitaria Peronista (JUP), Juventud Trabajadora Peronista (JTP), Movimiento Villero Peronistas (MVP), Movimiento de Inquilinos Peronistas and Unión de Estudiantes Secundarios (UES).

The Revolutionary Tendency started forming in late 1950s following the overthrow and exile of Juan Perón. Peronism entered a bitter conflict with the Catholic Church in 1954, which was then recognized as the main factor behind Perón's loss of power in 1955. Perón was also thought to have been excommunicated; in June 1955, the Vatican excommunicated those responsible for government's deportation of two Italian priests from Argentina, without specifying any individual. Perón maintained that the excommunication did not include to him, claiming that he was not involved in the deportation in any way. According to an American historian Robert Crassweller, "the excommunication dated in 1955 did not, technically speaking, apply to Perón, “for it failed to comply with certain requirements of canon law." During his exile, Perón's relations with the Catholic Church would steadily improve, and he was granted marriage with Isabel by the Church. According to historian David F. D'Amico, "Perón was later forgiven by the Church, for he died on July 1, 1974, a faithful Catholic, and was administered extreme unction [by the Vatican] immediately before his death."

The first radical Peronist organization that was formed and is considered the precursor of Revolutionary Tendency were the Uturuncos, "tiger men" in Quechuan, formed in 1955 and composed of twenty Peronists with nationalist and socialist sympathies. Based in the mountains of Tucumán, Uturuncos wanted to establish themselves as a revolutionary vanguard and a way of political agitation. Each members had the acronym MPL-ELN on their shirt sleeves, standing for Movimiento Peronista de Liberación - Ejército de Liberación Nacional (English: Peronist Liberation Movement-National Liberation Army). The main ideologue of the organization was Abraham Guillén, Spanish Republican exiled in Argentina. He formed the political program of the organization that advocated for a socialist revolution carried out by a revolutionary minority which would serve as the locomotive of mass mobilization.

Argentina felt the impact of the Cuban Revolution, and John William Cooke, a close associate of Perón who would emerge as the main representative of the Peronist left, moved to Cuba in 1960. Cooke earned a reputation of a militant labor leader in the late 1950s, organizing major 1958 oil workers' strike and the 1959 Lisandro de la Torre strike, which he tried to transform into a Peronist revolution. While in Cuba, Cooke associated Peronism with Fidelism, seeing the left-wing nationalism of Peronism and Marxism-Leninism of Fidelism as complementary; he wrote: "Nowadays nobody thinks that national liberation can be achieved without social revolution and therefore the struggle is also [one] by the poor against the rich... Since national liberation is indivisible from social revolution, there is no bourgeois nationalism, for the bourgeoisie's objective was to 'privatize the lucre and socialize the sacrifices." Cooke's concept of mixing national liberation with social revolution became the core concept of Revolutionary Tendency, and was embraced by Perón himself.

With the assistance of Cooke, the Cuban Revolution opened dialogue between the revolutionary Cuban government and Perón. Che Guevara appealed for unity amongst anti-imperialist forces in Latin America, and explicitly recognized Peronism as a fellow anti-imperialist movement. Perón himself praised the Cuban Revolution and discussed the parallels it had with his own 'revolution', and would increasingly adapt the Cuban rhetoric in the 1960s. Che Guevara subsequently visited Perón in Madrid, and argued that Peronism is "a kind of indigenous Latin American socialism with which the Cuban Revolution could side". Perón maintained a close relationship with Guevara and paid homage to him upon his death in 1967, calling him "one of ours, perhaps the best" and remarking that Peronism "as a national, popular and revolutionary movement, pays homage to the idealist, the revolutionary, Comandante Ernesto Che Guevara, Argentine guerrilla dead in action taking up arms to seek the triumph of national revolutions in Latin America."

The Peronist alliance with Guevarism forced the Argentinian left to reconsider their stance of Peronism. Prior to 1955, while some rank-and-file members of socialist parties defected to Perón and his party, Communist and Socialist movements generally dismissed Peronism as fascism. This would change with the emergence of the "New Left" in the late 1950s which agreed with Guevara's description of Peronism as a genuine anti-imperialist movement that needs to be approached in order to mobilize the Argentinian working class towards the revolution. This was also connected to the left's disappointment with the anti-Peronist Revolución Libertadora - the following cabinets not only repeated and escalated elements of Peronism that the Argentinian left objected to such as siding with the Church hierarchy and perceived corruption, but they also rolled back Peronist social and economic programs that the left approved of.

Revolutionary thought within Peronism then evolved following the aggiornamento of the Catholic Church brought about by the Second Vatican Council. The aggiornamento made the Church concern itself more with the poor, the plight of the working class, and the problems of capitalism and imperialism; recognizing the growing Catholic participation in popular class struggles, Vatican found it permissible to enter dialogue with Marxism. Pacem in terris by Pope John XXIII went as far as stating that many elements of Marxism were "worthy of approval". The Second Vatican Council formalized a new orientation of the Church - poverty, injustice and exploitation, especially that of imperialism and colonialism, were condemned as results of greed for wealth and power; Vatican urged Catholics to struggle for equality in name of love for their fellow man. The most radical expression at the Council was that of Maximos IV Sayegh, who declared that "true socialism is a full Christian life that involves a just sharing of goods and fundamental equality", and also Populorum progressio by Pope Paul VI that was a synthesis of the Vatican II ideas, attacking "inequality, the profit motive, racism, and the selfishness of the richer nations". Paul VI particularly stressed the idea of "tyranny", arguing that it is not just a matter of an oppressive political system but also of social and economic systems that "dehumanize and maintain the existence of widespread poverty".