The Khmer Loeu are found mainly in the northeastern provinces of Ratanakiri, Stung Treng, and Mondulkiri.

The Mon–Khmer-speaking tribes are the aboriginal inhabitants of mainland Southeast Asia, their ancestors having trickled into the area from the northwest during the prehistoric metal ages.

There have never been any treaties between a Khmer Loeu group and the government nor is Cambodia a signatory to the Indigenous and Tribal Peoples Convention.

The colonial French administration designated the highland ethnicities of Cambodia, Laos and Vietnam "Montagnards".

The term "Khmer Loeu" was crafted by the Sangkum Reastr Niyum government of Sihanouk's Cambodia in the 1950s.

Khmer Loeu was coined as a catch-all term to include all of the indigenous minority ethnic groups, most of which reside in the remote highlands of northeast Cambodia.

The Khmer Loeu cultivate a wide variety of plants, but the main crop is dry or upland rice grown by the slash-and-burn method.

Hunting, fishing, and gathering supplement the cultivated vegetable foods in the Khmer Loeu diet.

In the 1960s, the Cambodian government carried out a broad civic action program—for which the army had responsibility—among the Khmer Loeu in Mondulkiri, Ratanakiri, Stung Treng, and Koh Kong provinces.

In the late 1960s, an estimated 5,000 Khmer Loeu in eastern Cambodia rose in rebellion against the government and demanded self-determination and independence.

Following the rebellion, the hill people's widespread resentment of ethnic Khmer settlers caused them to refuse to cooperate with the Cambodian army in its suppression of rural unrest.

There is some evidence that in the 1960s and in the 1970s the Front Uni pour la Libération des Races Opprimés (FULRO—United Front for the Liberation of Oppressed Races) united tribes in the mountainous areas of southern Vietnam and had members from Khmer Loeu groups as well as from the Cham in Cambodia.

In the early 1980s, Khmer Rouge propaganda teams infiltrated the northeastern provinces and encouraged rebellion against the central government.

The major Khmer Loeu groups in Cambodia are the Kuy, Pnong, Stieng, Brao, Tampuan, Pear, Jarai, and Rade.

In the late 1980s, about 160,000 Kuy lived in the northern Cambodian provinces of Kampong Thom, Preah Vihear, and Stung Treng as well as in adjacent Thailand.

The Brao, Kreung, and Kavet inhabit the northeastern Cambodian province of Ratanakiri and adjacent Laos.

Many Tampuan live in villages close to Ratanakiri's provincial capital, Ban Lung, around a volcanic crater lake, Yeak Laom.

In Cambodia the Bunong are found in Mondulkiri, Kratié, and Kampong Cham provinces in villages consisting of several longhouses each of which is divided into compartments that can house nuclear families.

The Bunong practice dry-rice farming, and some also cultivate a wide variety of vegetables, fruits, and other useful plants as secondary crops.

Wealth distinctions are measured by the number of buffalo that a notable person sacrifices on a funereal or ceremonial occasion as a mark of status and as a means of eliciting social approval.

Two chief sorcerers, whose main function is to control the weather, play a major role in Pearic religion.

The Austronesian groups of Jarai and E De (also known as Rhade, or Rade) form two of the largest ethnic minorities in Vietnam.

In the past, sorcerers known as the "kings of fire and water" exerted political power that extended beyond an individual village.