Mauretania Caesariensis (Latin for "Caesarean Mauretania") was a Roman province located in what is now Algeria (and a small part of Morocco) in the Maghreb. The full name refers to its capital Caesarea Mauretaniae (modern Cherchell).

The province had been part of the Kingdom of Mauretania and named for the Mauri people who lived there. Formerly an independent kingdom, and later a client state of Rome, it was annexed into the Empire formally during the reign of Claudius and divided into two provinces about 42 AD. A third province, named Mauretania Sitifensis, was later split off from the eastern portion during the reign of Diocletian in 293 AD. During and after the Fall of the Western Roman Empire in the 5th century, most of the hinterland area was lost, first to the Vandal Kingdom and later to the Mauro-Roman Kingdom, with Roman administration limited to the capital of Caesarea. The land was reconquered by Rome during the reign of Justinian. This province was a part of Praetorian prefecture of Africa, later Exarchate of Africa. The Muslim conquest of the Maghreb brought an end to Roman rule in Mauretania, permanently this time, which became ruled by the Umayyad Caliphate as part of Medieval Muslim Algeria.