Ermanaric (d. between 370 and 376) was a King of the Ostrogoths.

As king, he ruled a vast empire in Ukraine. The exact limits of his territory are obscure, but it seems to have stretched south of the Pripet Marshes between the Don and Dniester rivers.

Ermanaric's name in his native Gothic was probably Aírmanareiks. He is referred to in literature throughout the Germanic world right up until the 13th century. Because of this his name takes many forms: in Jordanes' Getica he is Ermanaricus, in the Old English epic Beowulf he is Eormenric, in Old Norse he is Jörmunrekkr, and in Middle High German Ermenrich.

He is mentioned in two Roman sources—from the writings of Ammianus and in Getica by the 6th century historian Jordanes.

According to Ammianus, Ermanaric is 'a most warlike king' who eventually commits suicide, facing the aggression of the Huns, who invaded his territories in the 370s. His kingdom was destroyed and his people became subject to the Huns for about 75 years.

According to Jordanes, the king put to death a woman named Sunilda by tying her to two wild horses and driving them apart, because her husband had treacherously deserted him. Thereupon her two brothers, Sarus and Ammius, severely wounded Ermanaric. Variations of this legend had a profound effect on medieval Germanic literature, including that of England and Scandinavia. Jordanes claims that he successfully ruled the Goths until his death at the age of 110.