Oris was founded by Paul Cattin and Georges Christian in the Swiss town of Hölstein. They bought the recently closed Lohner & Co watch factory, and on 1 June 1904 the two men entered into a contract with the local mayor. They named their new watch company Oris after a nearby brook, and they began the industrial manufacture of pocket watches. In its founding year, Oris employed 67 people.

In 1906, the firm opened an assembly plant and second factory in the nearby town of Holderbank. Another factory followed in Como in 1908. By 1911, Oris had become the largest employer in Hölstein, with over 300 workers. By 1914, Oris had produced over a million watches. To entice more watchmakers, it built houses and apartments for its staff, and it expanded so that by 1929 it had additional factories in Courgenay (1916), Herbetswil (1925) and Ziefen (1925). Once all plants were operating at capacity, Oris boasted it could create “one watch every three seconds.”