Aprus or Apros (Ancient Greek: Ἄπρος), also Apri or Aproi (Ἄπροι), was a town of ancient Thrace and, later, a Roman city established in the Roman province of Europa.

Stephanus of Byzantium collects a quote of Theopompus that mentions Aprus. Pliny the Elder notes that Aprus is situated in the interior of Thrace, 22 M.P. from Resisto (likely the same as Bisanthe), 50 Roman miles from Bizya and 180 Roman miles from Philippi.

The city was re-founded as Colonia Claudia Aprensis in the mid-1st century AD, probably in connection with the emperor Claudius's annexation of Thracia, and was intended for retired members of the Roman military. It was situated on the Via Egnatia that ran from the Adriatic coast in the province of Illyricum to Byzantium, the city that was to become Constantinople.

In the 4th century, Aprus was the principal city of the region southwest of Heraclea, the capital of the province.

The city was called Theodosiopolis (Greek: Θεοδοσιούπολις) in documents of the 6th century, in honour of Theodosius II, emperor from 401 to 450, or of Theodosius I (347–395).

After the capture of Constantinople during the Fourth Crusade (1204), the Henry of Flanders, brother of Baldwin I, attacked the city and killed many of the citizens. The Latin Empire made Theodore Branas (called Li Vernas by Geoffroi de Villehardouin) lord of Aprus. In 1206, Tsar Kaloyan of Bulgaria destroyed the city, but Branas rebuilt it.

In the Battle of Apros of July 1305, the Catalan Company annihilated the Byzantine imperial army under Michael IX Palaiologos.

Its location is near the modern Turkish village of Kermeyan.