A renewal movement of the Roman Catholic Church, founded in Spain by a group of men in the 1940s, while they were refining a technique to train pilgrimmage leaders. The word Cursillo means "little courses." A young layman named Eduardo Bonnin who participated in the early years of the "little courses" helped develop the courses to the point that it became an active renewal movement in the church. By 1957, the movement had spread to North America, when the first American cursillo was held in Waco, Texas. It has since become a nearly universal (and officially approved) renewal movement of the Roman Catholic Church, and has even spread beyond the boundaries of the Catholic Church - Anglicans/Episcopalians, Lutherans, and Methodists have all adapted some variation of Cursillo to their own communities.

In addition to such groups as Episcopal Cursillo, the Cursillo method is also used by Via de Cristo, Walk To Emmaus, Kairos Prison Ministry, and Tres Dias.

The Cursillo method to this day focuses on training laypeople to become effective leaders over the course of a three day weekend that "Cursillistas" (those who have completed the weekend) do not not like to call a retreat.

The Cursillo movement is sometimes accused of being a secret society, because candidates are not told much in advance about what will take place on the three day weekend. Cursillistas defend this practice, as the emphasis of the weekend is on "not anticipating" but on participating. One emphasis of the weekend is on preparing those undergoing it to take the movement's methods back into the world, on what they call the "fourth day."