Aruj or Arouj (Turkish: Oruç Reis, Arabic: عروج بربروس, Spanish: Arrudye; c. 1474 – 1518) was a Barbary Pirate. He was the elder brother of Barbarossa Hayreddin Pasha and Ottoman Bey (Governor) of Algiers and Beylerbey (Chief Governor) of the West Mediterranean. He was born on the Ottoman island of Midilli (Lesbos in today's Greece) and was killed in a battle with the Spaniards at Tlemcen in the Ottoman Eyalet of Algeria.

He became known as Baba Aruj or Baba Oruç (Father Aruj) when he transported large numbers of Moriscos refugees from Spain to North Africa; he was known through folk etymology in Europe as Barbarossa (which meant Redbeard in Italian).