Spain is a country in which large numbers of castles have been built over the centuries; around 2,000 of these are still standing with their main walls still in a reasonable state of preservation. However, not many of these were built by the Christians as a defence against the return of the Moors. Also, few are of solely Moorish origin. Many other castles have been destroyed or are in a poor state of repair. For example, it is thought that about 400 Moorish castles once existed. From the few remains of these, it appears that the Moorish architecture was more advanced than that of the Christians.

The great castles of Spain that now remain are mainly from the 15C and 16C. These castles were built by the monarchs or by powerful nobles.

A well known example is the castle at Segovia. Another example, but well les known, is at Castellar de la Frontera in Andalusia.