Appia () was a town of ancient Phrygia, inhabited during Hellenistic, Roman, and Byzantine times. According to Pliny the Elder, it belonged to the conventus of Synnada. It became the seat of a bishop in the ecclesiastical province of Phrygia Pacatiana; no longer a residential bishopric, it remains a titular see of the Roman Catholic Church.
Its site is located near Pñnarcñk in Asiatic Turkey.