The Brazilian Landless Workers' Movement (MST) is the largest social movement in Brazil, one of the most powerful and successful grassroots movements in the world today, and a key contributor to the transnational struggle for Indigenous rights. It has managed to achieve this status even though the MST is not a formal organization (like a political party) and does not have a membership per se. The MST consists of all those who, since 1984, have challenged the lack of land reform in Brazil by occupying vacant, arable land owned by wealthy landlords and redistributing small parcels to landless workers. More than 350,000 families have gained access to more than fifteen million acres of land as a result of actions organized under the aegis of the MST.
The MST developed as a reaction to the unique conditions faced by rural labourers in Brazil. The country has the highest concentration of land ownership in the world, with 3 percent of the population owning two-thirds of the arable land. Furthermore, 60 percent of the farmland lies unused even as peasant families struggle to survive. The lack of land reform and the effective collapse of the Brazilian dictatorship in 1978 led to strikes in the cities (and the founding by urban labour unions of the Brazilian Workers' Party, or PT) and land occupations in the countryside. The name "Movimento Sem Terra" arose out of the nickname that the press gave to these actions and was first used in 1984.
The MST continues to work to redistribute land in Brazil. By drawing attention to rural injustices, it has contributed to the ongoing political transformation of Brazil (highlighted by the federal election victory of the PT in 2001), and has provided a model for other landless groups around the world.