The church of Santa María, also known as the church of the Assumption, is located in the town of Ainsa, in the autonomous region of Aragon.

Its construction began at the end of the 11th century and was completed in the mid-12th century. It was consecrated in 1181, according to existing documents. There is documentation showing the poor state of the tower and the previous cloister in the 14th century. Later, in the 16th century, the church was enlarged with the presbytery chapels and the nave vault, and in the 17th century the sacristy was added. Between 1972 and 1974, the church underwent a complete restoration.

The church, built of ashlar, has a rectangular shape and a semicircular apse. Its interior is sober and austerely decorated, characteristic of Romanesque architecture.

The crypt is located below the presbytery and is accessed via two staircases on both sides of the nave. It is a small room with three naves and four sections, separated by 18 columns.

The tower is the most outstanding element due to its size and sobriety. It is built of ashlar, is 30 metres high and has five floors. The top floor is particularly striking, with semicircular arched windows supported by capitals and columns.

The cloister, built in the 14th century, is attached to the north of the nave and has an irregular trapezoidal shape with a single floor.