Theravada Buddhism is the majority religion in Laos, practised by approximately two thirds of the population, followed by animism and ancestor worship. The remainder practise Mahayana Buddhism and Taoism, and a small percentage follow Christianity or Islam. As with many Buddhists of Southeast Asia, most Lao also make offerings to animist spirits and certain Hindu deities.

Lao-style Theravada Buddhism is a blend of indigenous and borrowed beliefs and rituals that owes much to the practices of neighbouring Thailand. In particular, the Hindu deities Brahma and Indra (who were adopted by Siam after the sacking of Angkor) have become icons in the Theravada Buddhist pantheon. Chinese and Vietnamese immigrants brought Mahayana Buddhism with them and today you may well see alongside images of the Buddha a representation of a Hindu god such as Ganesh or a Mahayana Buddhist deity such as Kuan Yin.

Following the Revolution, the communists banned alms-giving, effectively making it impossible to live as a monk, as it's against Buddhist precepts for monks to cultivate plants or raise animals for food. But popular outcry forced the government to rescind these measures, and Lao Buddhism has made a strong comeback.

The Buddhist Lao still harbour vestiges of animist beliefs, building " spirit houses " (miniature dolls- house- or temple-style buildings on a pedestal) on their property to provide a dwelling for the spirits who have been displaced from the land by humans. Some midland and highland tribal peoples in Laos are exclusively animist, and ancestor worship in different forms is also practised by many of the highland tribes that emigrated from China, including the Akha, Hmong and Mien.