The church of Santiago El Viejo, sometimes also known as Santiago de Los Caballeros and Santiago de Las Eras, is a Romanesque church in the city of Zamora.

It is located on the path of the Valorio stream, on the right bank of the Duero river, outside the city walls and opposite the castle of Zamora, in an area close to the Olivares neighbourhood. It is small in size, perhaps the smallest of the Romanesque churches in the city of Zamora, and is attached to the parish church of San Claudio de Olivares under the patronage of Santiago. The date of its foundation is not documented, although there is a first reference that places its existence in 1168, although it must have been built at least a century earlier, probably at the end of the 10th century or the beginning of the 11th century.

It was declared an Asset of Cultural Interest, with the category of monument, by Decree of 3 June 1931.

It is located outside the walls of the city of Zamora, near the Olivares district and opposite Zamora Castle. It belonged to the chaplains of the cathedral chapter, who opened it on the feast of its patron saint, St. James the Greater, celebrated on 25th July with a small pilgrimage.

It is known as Santiago de los Caballeros (Santiago de los Caballeros) because it is said that it was here, after having kept vigil, that the Cid Campeador was knighted by King Ferdinand the First.

It has a very pronounced rectangular floor plan in 11th century Romanesque style with a single nave with two bays, an apse with a semicircular apse and a straight section of presbytery with external buttresses. It has a simple doorway on the south façade through which access to the church is gained.