According to the 2006 estimate, Laos has a population of  6,368,481 people with an annual growth rate of 2.39%. Life expectancy of the total population is 55.5 years and infant mortality is high at 83 deaths per 1000 live births. On average, a woman has 4.68 children. Laos is a multi-ethnic society of which over 60% follows Buddhism. The literacy rate is high at 66.4%.

Due to inconsistent definitions and due to lack of ethnographic information about each group, there's some confusion in the ethnic group categorization. There was a time that sources when addressing the peoples of Laos provided that there were 60 ethnic groups in the country; while the 1985 consensus listed only 47 groups. Normally when asked about their ethnicity a Lao person is more likely to respond Lao Loum (Lowland Lao), Lao Theung (Midland or Low Mountain Lao) or Lao Sung (Highland or Mountain Lao). The Lao Government insists on the multi-ethnic nature of the Lao society which is indicated in the 1991 Constitution while emphasizing the commonality of the Lao population and reduce discrimination among the ethnic groups. For all these reasons and with regard to the interests of the travellers, the general classification of the Laos People into 03 indicated groups is widely accepted.

The Lao Loum accounts for 66% of the total population. They speak Thai-Kadai linguistic family and inhabit in river valleys of the lowland regions. The Lao Loum practises wet rice, mostly glutinous rice, cultivation. The Lao Loum lives in villages surrounded by paddy fields. Each village is headed by a chief who governs based on consensus from the community. Each village would have a Buddhist wat where all important decisions on the community are discussed and made. The houses of the Lao Loum are built on stilts of which the building process involves mutual help among villagers. Marriages used to be arranged by the parents, but nowadays the boys and girls choose their partners freely. After the marriage the boy may live and work at the girl's family for several years until they are ready economically to lead an independent life, even then many stick staying with the girl's family. Generally the Lao Loum has extended families and they maintain close relationship even among distantly blood-related people. Polygyny is not accepted among the Lao Loum.

The Lao Theung accounts for 24% of the total population. They belong to Austro-Asiatic linguistic family. Lao Theung ethnic groups are more diverse than those of the other groups. The Lao Theung inhabits in mountain valleys normally near a source of drinking water and practises mostly swidden agriculture. The Lao Theung lives in houses on stilts and their villages are smaller than those of the Lao Loum. Each Lao Theung village would have a village chief elected by the community. The village chief works as intermediary between the village and the government. Important decisions are made by the elderly committee. Besides, there's a ritual leader, whose position is hereditary, officiating at village rituals. Most of the Lao Theung are animists and practise ancestor-worshiping. Polygyny used to be allowed among the Lao Theung, though were not common. The Lao Theung is more patrilineal, though the groom must work at the bride's family as part of the payment for her.

The Lao Sung accounts for 10% of the total population comprising mostly hill tribe peoples who inhabit not only in Laos, but in the neighboring countries too. The Lao Sung migrated en mass into Lao area recently. They engage mostly in swidden farming which makes their communities more of migratory ones. The Lao Sung inhabits mostly in high mountain slopes (above 1000m in elevation). Ordinary rice and corn are the staple food of the Lao Sung. Some Lao Sung communities cultivated opium until recently. The Lao Sung traditionally  followed animism, though some have converted to Catholicism, or Protestant, or Christianity.

Apart from those 03 general groupings, there are also people of Vietnamese, Chinese and Khmer origin inhabiting in Laos.
 
Travelling in Laos, you are more likely to encounter all representatives from each of the  above groups. If you take an adventure tour, you'll have more chances to stay with one of the Lao Sung communities.