Alcazarén is a town and municipality in the Province of Valladolid, part of the autonomous community of Castile and León, Spain.

Its name originates from the Arab "al-qasrayn" which means "the two castles".

In the Tierra de Pinares region it is located 35 km South of the province's capital (41.3725° N, 4.6714° W).

It occupies an area of 48 km² with a 33.51 km perimeter.

This article about a location in the province of Valladolid, Spain is a stub.