The majority (88%) live in northern Laos where they constitute the largest minority ethnic group, comprising eleven percent of the total population.

[3] The Khmu can also be found in southwest China (in Xishuangbanna in Yunnan province), and in recent centuries have migrated to areas of Burma, Thailand and Vietnam (where they are an officially recognized ethnic group).

In the People's Republic of China, however, they are not given official recognition as a separate "national" group, but are rather classified as a subgroup of Bulang.

[5] There are more than 568,000 Khmu around the world, with populations of 500,000 in Laos, 73,000 in Central Highlands of Vietnam, 10,000 in Thailand, 10,000 in China, and an estimated 8,000-10,000 in the United States.

[7][8] Many of the Khmu in Thailand have arrived recently from Laos and Vietnam, also as refugees from the Vietnam War and subsequent communist governments, although cross-border migrations into Thailand's Nan, Phayao and Chiang Rai provinces for new farm land and work in the teak industry began as much as 200 years ago.

[5] In their mountain refuges, the various Khmu settlements became isolated, surrounded and partially influenced by the dominant groups of their respective areas.

They are often contrasted with the Khmu Roek who live higher up in the hills and retain some older customs that other groups have abandoned.

[5] Khmuic peoples refers to a group of ethnicities of mainland Southeast Asia that speak closely related languages and follow similar customs and traditions.

It is believed, based on linguistic, cultural and historical evidence, that these now-disparate groups are descended from a homogeneous ethnicity that may have been among the first populations to settle northern Indochina.

This historical Khmuic people inhabited areas far larger than at present,[5] including northern lowland areas of at least present day Thailand and Laos, until absorbed or pushed into mountainous refuges by successive Mon and Khmer empires and the later arrival of various Tai peoples.

[14] Laotian Khmu communities generally have localized justice systems administered by the village elders.

[12] The story-telling sessions involve the sharing of silver pipes (originally opium, but now predominantly tobacco).

[12][13] In Laos, Khmu are reputed for practicing magic, and some families still engage in the casting of spells and telling of fortunes.

In ancient time Khmuic people celebrated new year festival on the first waxing moon day of the first lunar month.

[14] There are three explanations for this directionality of house construction: 1. to expel devils, ghosts and bad spirits out of the houses (ancient Khmuic people believed that devils, ghosts or bad spirits fear sunlight); 2. to expel and wash out bacteria and any kinds of small insects dangerous to body and health; 3.

[13] In cases relating to the harvesting season, Khmuic people also respect the sun as a symbol of clear sky or rain-less weather.

This is why in the 'Moun Greh ceremony, Khmuic people hit the yan (bronze drum) to thank the sun for shining well during the rice harvesting; and that is why Khmuic people also call bronze drum as “heurbang greh” (harvest gong); in the present day this kind of practice is rare.

[13] Dances to propitiate the rice goddess are common among the Khmu people; they are performed in order to ensure a good harvest.