Buddhism is the primary religion of Laos. The Buddhism practiced in Laos is of the Theravada tradition. Lao Buddhism is a unique version of Theravada Buddhism and is at the basis of Lao culture. Buddhism in Laos is often closely tied to animist beliefs and belief in ancestral spirits, particularly in rural areas.

The percentage of the population that adheres to Buddhism in modern Laos is variously reported, the CIA World Factbook estimates 65% of the total population have taken refuge in the Three Jewels. The creation of accurate estimates of the number of Buddhists in Laos is complicated by the paucity of information made available by the Laotian government, and the close connection between Buddhist and animist practices in Laos could make the numbers of nominal adherents of both Buddhism-Animism as much higher as over 90% because these traditions have influenced on mostly Lao people. It is still exclusive significant numbers of Chinese or Vietnamese Mahayana Buddhists.