Asad al-Din Shirkuh bin Shadhi (died 1169) was an important Muslim military commander, and uncle of Saladin.

He was originally from a Kurdish village in Armenia near the town of Dvin . He was the son of Shahdi, a Kurdish ruler, and was the brother of Ayyub, the founder of the Ayyubid dynasty. When Ayyub lost Tikrit in 1138 he and Shirkuh joined Zengi's army, and Shirkuh served under Nur ad-Din who succeeded Zengi in Mosul. Shirkuh was later given Homs as a vassal state of Mosul.

In 1163 he convinced Nur ad-Din to send him to Egypt in to settle a dispute between Shawar and Dirgham over the Fatimid vizierate. Shawar was restored and Dirgham was killed, but after quarrelling with Shirkuh Shawar allied with Amalric I of Jerusalem, who marched into Egypt in 1164 and besieged Shirkuh at Bilbeis. In response Nur ad-Din attacked the Crusader states and almost captured the Principality of Antioch.

Shirkuh was sent back into Egypt in 1167, with Shawar once again allying with Amalric. Amalric besieged him in Alexandria until he agreed to leave; a Crusader garrison, however, remained in Egypt and Amalric allied with the Byzantine Empire, planning to conquer it entirely. Now Shawar sought help from Shirkuh. Shirkuh avoided a pitched battle with the Crusaders, who in any case did not have the resources to conquer Egypt and were forced to retreat.

In January of 1169 Shirkuh entered Cairo and had Shawar executed. He set himself up as vizier, but died two months later. He was succeeded by his nephew Saladin, who had served with him on his campaigns in Egypt.

Shirkuh's name is Persian and means "Mountain's Lion".