Yabghu (Old Turkic: 𐰖𐰉𐰍𐰆, romanized: yabɣu, simplified Chinese: 叶护; traditional Chinese: 葉護; pinyin: Yèhù), also rendered as jabgu, djabgu or yabgu, was a title early Turkic states, roughly equivalent to viceroy. The title carried autonomy in different degrees, and its links with the central authority of khagan varied from economical and political subordination to superficial political deference. The title had also been borne by Turkic princes in the upper Oxus region in post-Hephthalite times.

The position of yabghu was traditionally given to the second highest ranking member of a ruling clan, with the first highest ranking being the kagan. Frequently, the yabghu was a younger brother of the ruling khagan, or a representative of the next generation, called shad (blood prince). Mahmud Kashgari defined the title as "position two steps below Kagan", listing an heir apparent shad a step above yabghu.

As the khaganate^{[clarification needed]} decentralized, the yabghu gained more autonomous power within it, and historical records name a number of independent states with "yabghu" being the title of the supreme ruler. One prominent example was the Oghuz Yabgu State in Middle Asia, which was formed after the fragmentation of the Second Turkic Khaganate in the 740s. Another prominent example was the Karluk Yabghu, the head of the Karluks which, in the 766, occupied Suyab in the Jeti-su area, and eventually grew into a powerful Karakhanid state.

There are at least several proposals regarding the origin of yabghu: