Ligosullo is a frazione located in the Province of Udine within the Friuli-Venezia Giulia region of northeastern Italy. It is situated approximately 110 kilometres northwest of Trieste and about 50 kilometres north of the city of Udine.
Historically, Ligosullo functioned as an independent comune. However, on February 1, 2018, it was merged with Treppo Carnico to form the new municipality of Treppo Ligosullo.