The Diocese of Asia is a diocese of the later Roman Empire, incorporating the provinces of western Asia Minor and the islands of the eastern Aegean Sea.

The diocese is established after the reforms of Diocletian, is subordinate to the Praetorian prefecture of the East, and is abolished during the reforms of Justinian I in 535.It is one of the most populous and wealthy dioceses of the Empire, and includes 11 provinces: Asia, Hellespontus, Pamphylia, Caria, Lydia, Lycia, Lycaonia, Pisidia, Phrygia Pacatiana, Phrygia Salutaria and Insulae.