Aju (or Achu) (1227–1287) was a general and chancellor of the Mongol Empire and the Yuan Dynasty. He was from the Jarchud clan of the Mongol Uriankhai. His grandfather was Subutai, the honored general and Noyan of Genghis Khan; his father was Uryankhadai.
In 1253 he followed his father and subdued western Chinese people and conquered the Kingdom of Dali. Uryankhadai and Aju led 3,000 Mongols and more than 10,000 troops from Dali tribes to northern Vietnam in 1255. The king of the Trần Dynasty agreed to send tribute after his defeat in open battle; this lasted until the reign of Kublai.
He and his father supported the Great Khan Möngke and Kublai's forces in 1258. Aju commanded a tumen, 10,000 men in his earlier career. They conquered 13 cities within 2 years and destroyed 40,000 troops of the Song Dynasty while his father was ill. After the occupation of Chingzhoua and Yovajiyu, Uryankhadai met prince Kublai at Echjou.
When Kublai succeeded the throne in 1260, Aju stayed in his palace. The following year, he was ordered to lead Yuan troops in Lianshui . He crushed Song armies and navies from 1261 to 1275. He captured Fancheng by using Khotan artillery during the Battle of Xiangyang and its governor committed suicide.
In 1276, Aju was appointed to defend Beshbalik from Kaidu, a grandson of Ögedei. He died after the defeat of prince Sarban, who revolted against his master Kublai, in 1287. But some sources mention he died en route in 1286.