Cassacco () is a (municipality) in the Regional decentralization entity of Udine in the Italian region of Friuli-Venezia Giulia, located about northwest of Trieste and about northwest of Udine. As of 31 December 2004, it had a population of 2,880 and an area of .
The municipality of Cassacco contains the (boroughs) Conoglano, Martinazzo, Raspano, and Montegnacco.
Cassacco borders the following municipalities: Colloredo di Monte Albano, Magnano in Riviera, Tarcento, Treppo Grande, Tricesimo.
Cassacco is twinned with: