The A? Qoyunlu or Ak Koyunlu, also called the White Sheep Turkomans (Azerbaijani: A?qoyunlular, Turkish: Akkoyunlular, Turkmen: Akgo羸unly, Persian: 堞? ???????), was a Sunni Oghuz Turkic tribal federation that ruled parts of present-day Eastern Turkey, Armenia, Azerbaijan, northern Iraq, and Iran from 1378 to 1501.

The Aq Qoyunlu Turkomans first acquired land in 1402, when Timur granted them all of Diyar Bakr in present-day Turkey. For a long time, the Aq Qoyunlu were unable to expand their territory, as the rival Kara Koyunlu or 'Black Sheep Turkomans' kept them at bay. However, this changed with the rule of Uzun Hassan, who defeated the Black Sheep Turkoman leader Jah?n Sh?h in 1467.

Following Sultan Ya'qub's death, civil war erupted, the Aq Qoyunlus destroyed themselves from within, and they ceased to be a threat to their neighbors. The Safavids and the Aq Qoyunlu met in battle at Nakhchivan in 1501, and the Safavid leader Ismail I forced the Aq Qoyunlu to withdraw.

In his retreat from the Safavids, the Aq Qoyunlu leader Alwand destroyed an autonomous splinter Aq Qoyunlu state in Mardin. The last Aq Qoyunlu leader, Murad, brother of Alwand, was also defeated by the same Safavid leader. Though Mur?d briefly established himself in Baghdad in 1501, he soon withdrew back to Diyar Bakr, signaling the end of the Aq Qoyunlu rule.