Osor (Italian: Ossero) is a village and a small port on the Croatian island of Cres, in Primorje-Gorski Kotar county.

In Roman times, Osor, then called Apsoros (Ancient Greek: Ἄψωρος), also used to refer to the whole island of Lošinj,[3] was an important center of trade on the route to the ports of Northern Adriatic.

Due to malaria, it was ultimately abandoned as the administrative center of the island in favor of the town of Cres.

The area was taken by the Ottoman Empire in 1621 and held for a short time, during which its Christians travelled to Šibenik to fulfil their Easter duty of Confession and Communion.

[6][7][8] (all Roman Rite; very incomplete : first centuries unavailable) It is today listed by the Catholic Church as a [9] since 1933, when the diocese was nominally restored as a titular bishopric Osor, also named Absorus in Latin and Ossore in Curiate Italian.