The ethnic Lao and some Tai groups are Theravada Buddhists. There are also beliefs usually labeled animistic and beliefs associated with shamanism that involve house spirits, village spirits, district spirits, city spirits, and spirits of the realm. At the higher levels these spirits overlap strongly with Buddhism and are embodied in stupas and temples. These beliefs in territorial spirits also are held by the non-Buddhist Tai.

The majority of the population has various beliefs concerning sacred places and objects. Ancestor worship is strong among lineally organized groups. Christianity has made inroads among nonethnic Lao, with the Khmu, Hmong, Vietnamese, and Chinese most often being converts.

Source: http://www.everyculture.com/Ja-Ma/Laos.html