The Kidarite (Chinese: Ki-To-Lo) were a dynasty of the "Ki" clan, probably originating from the Uar people. They were part of the complex of tribes known collectively as Xionites or "Hunas".

During the 4th-5th century they established the Kidarite kingdom.

The Kidarites, a nomadic clan, are supposed to have arrived in Bactria with the great migrations of the second half of the 4th century. When Shi Le established the Later Zhao state, it is thought that many of the Uar from around Pingyang (平陽, in modern Linfen, Shanxi) fled west along the Silk Road. This caused the Xionites to encroach upon Khorasan and the frontiers of the Kushan state around 320 AD.

The Kidarite king Grumbat mentioned by Ammianus Marcellinus was a cause of much concern to the Persians. Between 353 AD and 358 AD, the Xionites under Grumbat attacked in the eastern frontiers of Shapur II's empire along with other nomad tribes. After a prolonged struggle they were forced to conclude a peace, and their king Grumbat accompanied Shapur II in the war against the Romans. Victories of the Xionites during their campaigns in the Eastern Caspian lands are described by Ammianus Marcellinus: