Orthosia (Ancient Greek: Ὀρθωσία) was a town of ancient Caria, inhabited during Hellenistic, Roman, and Byzantine times. It was not far from Alabanda, on the left bank of the Maeander River, and apparently on or near a hill of the same name. Near this town the Rhodians gained a victory over the Carians. It was the seat of a bishop from an early date, and, while no longer a residential bishopric, it remains under the name Orthosias in Caria a titular see of the Roman Catholic Church.
Its site is located near Ortas in Asiatic Turkey.
This article incorporates text from a publication now in the public domain: Smith, William, ed. (1854–1857). "Orthosia". Dictionary of Greek and Roman Geography. London: John Murray.
Coordinates: 37°49′27″N 28°13′41″E / 37.824122°N 28.228037°E