In Vietnam, most Lu live in Lai Châu Province, and their population was 5,601 in 2009. In China, they are officially recognized as part of the Dai ethnic group. The 2000 census counted about 280,000 Dai people speaking Lü language. The population in Thailand, where they are called Thai Lue (Thai: ไทลื้อ), was in 2001 estimated to be approximately 83,000. Most Thai Lue in Thailand live in Nan, Chiang Rai, Phayao and Chiang Mai Province.
In Vietnam, Lu are the indigenous people in Mường Thanh ("Land of the God of Tai people", Tai Lü: muong theng). They had built Tam Vạn wall in Mường Thanh and managed there for 19 generations before Hoàng Công Chất, a Thái leader, came. Nowadays, nearly all Vietnamese Lu live in Lai Châu Province. The Lu take their father's last name and have the middle name Bạ (for males) and Ý (for females). Their religion is TheravadaBuddhism. They sing khắp lự and play pí me luk ("mother-children" flute).