Oulx is a comune (municipality) in the Province of Turin in the Italian region Piedmont, located about 70 km west of Turin, in the Susa Valley on the border with France.

Like many other towns in the Susa Valley, Oulx has different names reflecting the area's multiple linguistic traditions. One theory of the name's origin is that it derives from Ulkos, the name of a leader of the Celtic Salassi tribe. Another theory holds that the derivation is from Ultor, a title of the god Mars, to whom a temple in the area was dedicated. These names were first rendered as Ulces, and later Ulcium on maps in the Middle Ages, in Latin. From the older forms, the name became Olcs in the Occitan language and was later Francized as Oulx. As part of Italian Fascist Italianization, Oulx was renamed Ulzio from 1928 to 1947. However, this form is considered etymologically incorrect, deriving from the Latin "Ultium" rather than "Ulcium."

Today, the municipality is called Oulx in Italian and French, Ours in the local Cisalpine Occitan (a Vivaro-Alpine subdialect; using an alternate orthography),Ors [uɾs] in standard Occitan (using classical orthography), and Ols [ʊls] in Piedmontese as well as in the Cisalpine Occitan standard (using classical orthography).