Calatayud (2002 pop. 18 531) is a town in the province of Zaragoza in Aragon, Spain.

It is the second-largest town in the province after the capital, Zaragoza, and the largest town in Aragon other than the three provincial capitals.

It is the seat of the comarca of Comunidad de Calatayud .

The AVE high-speed train line from Madrid to Lleida (and eventually Barcelona) stops in Calatayud.