Masuna (fl. 508) was a Romano-Moorish king in Mauretania Caesariensis (western Algeria). He ruled the Kingdom of Altava (Regnum Maurorum et Romanorum or "Mauro-Roman kingdom" in English), a Christian Berbers kingdom that existed in Tamazgha from the 4th century AD until the Muslim conquest of the Maghreb.
Masuna is known only from an inscription on a fortification in Altava (modern Ouled Mimoun, in the region of Oran), dated 508, describing him as "King of the Moorish and Roman peoples". He is known to have possessed Altava and at least two other cities, Castra Severiana and Safar, as mention is made of officials he appointed there.
Although evidence is scant, it is presumed that Masuna (who was probably a Christian) ruled over a Romano-Moorish kingdom that stretched (or had ambitions to stretch) over a substantial part of Mauretania Caesariensis. It may have been originally a successor state to the western Roman Empire (similar to Aegidius in Gaul) that managed to maintain its independence and resist occupation by the Vandals, or it may have been carved out later when Vandal rule weakened. It is almost certain Masuna was a Berber, possibly descended from a Romano-Berber family appointed as federate commanders in Roman times, who simply continued after the Vandal invasion, or a Berber warlord who extended his rule in the chaos of Vandal times beyond the pastoralist Berber tribes (contemporaneously known as "Mauri" or Moors), to also cover the Romanized cities of Mauretania.
Masuna may be the same person as the Berber chieftain called "Massonas" by Procopius in 535 AD, who allied with the Byzantines during the Vandalic War. Massonas is said to have encouraged the Byzantine general Solomon, the Prefect of Africa, to launch an invasion of the Moorish kingdom of Numidia.
Masuna may have been succeeded as Moorish king of Altava by Mastigas in the late 530s (known from coinage), and the more famous Garmul in the 560s.