Yaqub b. Uzun Hasan (Persian: یعقوب بن اوزون حسن, Azerbaijani: سلطان یعقوب) commonly known as Sultan Ya'qub (سلطان یعقوب) was the ruler of Aq Qoyunlu dynasty from 1478 until his death in December 14, 1490. A son of Uzun Hasan, he became the ruler of the dynasty after the death of Sultan Khalil. The borders of Aq Qoyunlu dynasty remained stable during his reign. In his book Alam-Aray-i Amini, Fazl b. Ruzbihan Khunji praised him as a decent successor of Uzun Hasan. Other historians also praised Ya'qub for his patronage of scientists and poets.
During Yaqub's reign, Alvand Beg and Kusa Haji revolted against the Aq Qoyunlus in Shiraz and Isfahan respectively, but both revolts were crushed. The biggest revolt during his reign was that of Shaykh Haydar, the father of Ismail I, which resulted in the death of Haydar.
Ya'qub became severely ill and died in December 14, 1490 in Karabakh. A number of scholars believe that he was poisoned by his wife.