Casalattico (Campanian: Casale) is a comune (municipality) in the Province of Frosinone in the Italian region of Lazio.

It is home to a summer Irish festival celebrating the local families that moved to Ireland with the twinning of the town with Naas in County Kildare.

People from the Monforte and Casalattico area were transported by the occupation German military forces to the Concentration camp at Cesano.

At the end of hostilities in 1945 in the nearby valley towns the level of destruction was huge, leading to a large immigration wave.

The Casalattico area includes the medieval ruins of the ancient Benedictine monastery of Sant'Angelo in Pesco Mascolino (780 AD), and an earlier example of a Roman bridge on the Melfa river.