The Yao ethnic group migrated from Laos into Thailand about a century ago, residing in highland regions of Chiang Rai, Chiang Mai, Nan, Phayao, Lampang, Tak, Kamphaengphet, and Sukhothai Provinces. Their economic system is based on shifting cultivation, growing rice, corn and opium as cash crops, and pepper, chili and potatoes for family consumption and sales. After marriage, the woman moves in to live with the man’s family. The family is of the extended type. The head of the household is a man in charge of every family member. In regard to social order, a shaman who conducts rituals knows best about social regulations, practices and traditions. In addition, the Yao respect seniority, with elderly men providing recommendations and decision making. The ethnic group is animist worshipping ancestors’ spirits, supernatural powers, and Taoism from China dating back to about 600 years ago. The two beliefs have been integrated until it has become unique to the group. The Yao believe that supernatural power can cause sickness, death, luck, or fertility. Therefore, it is imperative to create a good relationship between spirits, supernatural powers and humans by conducting sacrificial rituals. A shaman functions as a medium between the two worlds. However, some Yao people have converted to Buddhism and Christianity. Although the Yao carry Thai identity cards and hold Thai nationality, they are sometimes called hilltribe. Nevertheless, when compared to other minority ethnic groups, the Yao have better socio-economic conditions.