The Dai is the officially recognized name of an ethnic group living in southern Yunnan Province of China, and also in Laos, Vietnam, Thailand, and Myanmar. They are also known as the Lü, Lue, or Thai Lue and Tai Nüa. The Dai people form one of the 56 ethnic groups officially recognized by the People's Republic of China.

Although they are officially recognized as a single people by the Chinese state, the Dai people form distinct cultural and linguistic groups. The two main languages of the Dai are Lü and Tai Nüa. Both are Tai languages, a group of related languages that includes Thai, Lao, and Zhuang, and part of the Tai-Kadai language family. Lü and Tai Nüa have distinct scripts, derived from the Thai alphabet. The Dai peoples follow their traditional religion and Theravada Buddhism, and maintain similar customs and festivals to the other Tai-speaking peoples.

Dai people are typically farmers, growing a variety of tropical crops such as pineapples, in addition to the staple crop of rice. Many Dai people live near the Mekong river where it meanders through the far south of Yunnan.