Santa Maria la Longa (Friulian: Sante Marie la Lungje) is a comune (municipality) in the Regional decentralization entity of Udine in the Italian region of Friuli-Venezia Giulia, located about 50 kilometres (31 mi) northwest of Trieste and about 15 kilometres (9 mi) southeast of Udine. The Municipality is situated in a central position in the plain of Friuli with the chief town Santa Maria la Longa and the hamlets of Tissano, Mereto di Capitolo, Santo Stefano Udinese and Ronchiettis.

Santa Maria la Longa borders the following municipalities: Bicinicco, Gonars, Palmanova, Pavia di Udine, Trivignano Udinese.

The settlements in the territory of Santa Maria la Longa are documented only starting from the Roman period; in fact, many archaeological finds scattered in a uniform way over the whole area date back to that age.

It is worth mentioning the hamlet of Tissano, which was destroyed by the Turks in 1477; its antiquity is proven by the finding - in the 1950s - of a Lombard cemetery.