Liberation theology is a movement, which began in Catholic theology that seeks liberation for the poor and oppressed. The roots of liberation theology lie in the experience of those in Latin America. In 1968, bishops at the Second Latin American Episcopal Conference in Medellín, Colombia issued a statement that:
in many places in Latin America there is a situation of injustice that must be recognized as institutionalized violence, because the existing structures violate people's basic rights: a situation which calls for far-reaching, daring, urgent and profoundly innovating changes
Broadly, liberation theology attempted to see the Bible and Christianity through the lens of poverty, and take the insights derived from that perspective to help bring about socioeconomic reforming, attempting to change the structures and instituions in society that perpetuated inequality.
Some of the best-known theologians in the liberation theology movement include the Peruvian theologian and priest Gustavo Gutierrez (who wrote the 1971 work A Theology of Liberation), the Brazilian theologian Leonardo Boff, El Salvador Archbishop Oscar Arnulfo Romero, Camillo Torres, José Porfirio Miranda and others.
The work has extended beyond its Catholic origins. Friends of Sabeel-North America has developed a pararigm for Palestine, as developed by Canon Naim Ateek, Founder/Director, Sabeel Ecumenical Liberation Theology Center, Jerusalem. 
- FAQ, Friends of Sabeel-North America