About half the country's people are ethnic Lao, the principal lowland inhabitants as well as the politically and culturally dominant group. The Lao are descended from the Tai people who began migrating southward from China in the first millennium A.D. Mountain tribes of Miao-Yao, Austro-Asiatic, Tibeto-Burman -- Hmong, Yao, Akha, and Lahu -- and Tai ethno linguistic heritage are found in northern Laos. Collectively, they are known as Lao Sung or highland Lao. In the central and southern mountains, Mon-Khmer tribes, known as Lao Theung or mid-slope Lao, predominate. Some Vietnamese and Chinese minorities remain, particularly in the towns, but many left in two waves--after independence in the late 1940s and again after 1975.

The predominant religion is Theravada Buddhism. Animism is common among the mountain tribes. Buddhism and spirit worship coexist easily. There also are small numbers of Christians and Muslims.

The official and dominant language is Lao, a tonal language of the Tai linguistic group. Mid-slope and highland Lao speak an assortment of tribal languages. French, once common in government and commerce, has declined in usage, while knowledge of English--the language of the Association of Southeast Asian Nations (ASEAN)--has increased in recent years.