Dai is a state of the Xianbei clan of Tuoba, during the era of Sixteen Kingdoms in China.

It exists from 310 to 376 CE, with its capital at Shengle (near modern Holingol county of Hohhot, Inner Mongolia).The name "Dai" originates when Tuoba Yilu is appointed Duke of Dai by the Western Jin in 310 CE, as a reward for helping Liu Kun, the Governor of Bingzhou, fight against the Xiongnu state of Han Zhao.

The fief is later promoted from a duchy to a principality.

Dai is conquered in 376 by the Former Qin state, and its descendants later establish the Northern Wei Dynasty in the 4th century.