Arghun Agha, also Arghun Aqa or Arghun the Elder (died 1278) was a Mongol noble of the Oirat clan in the 13th century. He was a governor in the Mongol-controlled area of Persia from 1243 to 1255, before the Ilkhanate was created by Hulagu. Arghun Agha was in control of the four districts of eastern and central Persia, as decreed by the great khan Möngke Khan.
When he was young, his father sold his son Arghun to Ilugei of the Jalayir, tutor of Ogedei Khan. During his years with the Ogedeyid family, he gained reputation among the members of the Royal blood because he was well educated. Arghun started his career as court official during the reign of the Qaghan Ogedei. Later on, the latter's consort, Toregene Khatun, appointed him civil governor in Transoxiana in c.1242. Ascelin of Lombardia might have met him while he was at the court of Baiju in c.1247. In 1259-61 he directed punitive operations against rebels in Georgia, and then was sent to Khorasan to fight the Golden Horde. He is described as faithful servant of the Qaghan in Persian sources while the Georgian and Armenian sources say he was cruel and violent overseer. However, one Georgian chronicle mentions he was a friend of equity, trustful in his language, a deep thinker, and profound in counsel. It also says Arghun conducted the empire-wide census in Russia, Arctic, Alania, Pontic steppe, Georgia, Armenia, and Anatolia.