Castel Gandolfo is a small Italian town in Lazio that occupies a height overlooking Lake Albano about 30 km south-east of Rome, on the Alban Hills. It is best known as the summer residence of the Pope.

Archaeological findings from the 16th century BC have been found in the area of what is now Castel Gandolfo.

The modern city occupies the site of ancient Alba Longa, capital of the Latin League. Its name is derived from a fortification of the ducal Gandolfi family (of Genoese origin, named after St. Gondolfus) in the 12th century, which passed to the Savelli family from whom the Apostolic Camera purchased it in 1596 for 150,000 scudi. Pope Clement VIII was the first pope to come to Castel Gandolfo, but the rebuilding of the old castle was the project of Urban VIII who first came in 1626.