Reducción de Santa María la Mayor (Reduction of Holy Maria Major), located in the Santa María Department of the Misiones Province, Argentina, was one of the missions or reductions founded in the 17th century by the Jesuits in the Americas during the Spanish colonial period.

[1] The Jesuit reduction of Santa María la Mayor was founded in 1626, and by 1744 it held a population of 993.

In 1984 the ruins of the reduction were declared a World Heritage Site by UNESCO, together with three other reductions in the area of Argentina and one in Brazil, all formerly part of the Province of Paraguay during the colonial era.

They are not as well preserved as those of San Ignacio Miní, also in Misiones.

This article about a place in Misiones Province, Argentina is a stub.