Istämi Yabgu was the Western govenor of the Celestial Turkic Empire (Göktürk Qaghanate). As the brother of Bumin Qaghan he ruled the western region of their empire. His son was Tardu.

During his rule he established diplomatic relations with the Persian and Byzantine Empires, defeated the Hepthalites, and acted as an elder statesman during the distintegration of the Eastern half of the empire. We know a great deal about him from the dipomatic missions of the Byzantine Empire.

Gokturks