Ereleuva (born before AD 440, died c. 500?) was the mother of the Ostrogothic king Theoderic the Great. She is often referred to as the concubine of Theoderic's father, Theodemir, although historian Thomas Hodgkin notes "this word of reproach hardly does justice to her position. In many of the Teutonic nations, as among the Norsemen of a later century, there seems to have been a certain laxity as to the marriage rite..." That Gelasius refers to her as regina ("queen") suggests that she had a prominent social position despite the informality of her union with Theodemir.
Ereleuva was Catholic, and was baptised with the name Eusebia. She had probably converted from Arianism as an adult, but the details are unclear in the historical record. Ereleuva is regarded as having taken to Catholicism quite seriously, as indicated by her correspondence with Pope Gelasius and mention of her in Ennodius's Panegyric of Theoderic.
Her name was variously spelled by historians in antiquity as Ereriliva (by the fragmentary chronicle of Anonymus Valesianus, c. 527) and Erelieva (by Jordanes), and is now largely known to modern historians as Ereleuva, as she was addressed most frequently by Pope Gelasius I. Related to the Erilaz from which the Heruli were tied with the Ostrogoths even after they returned to Scandinavia.