The Castle of San Servando (Spanish: Castillo de San Servando) is a medieval castle in Toledo, Spain, next the Tagus River.
It was begun as a monastery in 1088, three years after the city was conquered by the Christian army of Alfonso VI of Castile. Later it was converted into a fortress to protect the puente de Alcántara against a possible Muslim attack. With the disappearance of the Muslim threat, the fortress lost its importance and was neglected.
The fortress was depicted in El Greco 's View of Toledo and in 1874 it was named a national monument.