Octar was a Hunnic ruler. His rule dates are unknown, yet it is believed he started around 420 AD. His relationship to the previous Hunnic ruler Charaton, mentioned by Olympiodorus in 412 - 413, is uncertain.

According to contemporary historical sources, Octar ruled together with his brother Rugila in the form of a dual kingship, similarly to his nephews Attila and Bleda. He is very probably identical with the Hunnic leader Uptaros, who died ca. 430 (allegedly from the excess of food) during a military campaign against the Burgundians on the Rhine. The next day, his army was attacked by the Burgundians and destroyed. After Octar's death, his brother Rugila ruled as a sole king of the Huns until his death ca. 435.