Tolmezzo (Friulian: Tumieç; Slovene: Tolmeč; archaic German: Tolmein or Schönfeld) is a town and comune (municipality) in the Regional decentralization entity of Udine, part of the autonomous Friuli-Venezia Giulia region of north-eastern Italy.

The commune also includes the five frazioni (boroughs) of Cadunea (Friulian: Cjadugnee), Caneva (Cjanive), Casanova (Cjasegnove), Fusea (Fusee), Illegio (Dieç), Imponzo (Dimponç).

The existence of Tolmezzo (called Tolmetium) is first documented in the late 10th century, when it was part of the Patriarchate of Aquileia, but it has been suggested that the town stemmed from a very ancient pre-Roman settlement.

In 1420, it was annexed to the Republic of Venice, but its trades and industries did not suffer from the change, and the city maintained its privileges.

In 1797, by the Treaty of Campo Formio, it was handed over to the Austrian Empire, and after a short Napoleonic rule, it was included in the client Kingdom of Lombardy–Venetia.