The Yao have a mixture of religious beliefs derived from ancestor worship, Taoism, animism, Confucianism, polytheism, astrology, geomancy and ancestor worship.  Their many rituals and ceremonies involve placating various spirits, honoring ancestors and determining propitious times to make important decisions or do significant actions.  Taoists worship a large pantheon of spirits, including the spirit of heaven, the earth, the mountains and the soil.  The yao adopted Taosim around one thousand years ago.  Their tribal religion involved three main gods, a nature god, a god over living beings, and a god of the dead.  A specific ancestor spirit that they honor is P'an Hung, their first ancestor.  Another is P'an Ku, the creator of the world.

The Lantien subgroup of the Yao believe that when a bad person dies, he goes to hell.  Hell is seen as like a dark forest without any clearings or villages.  They believe that good people will go to heaven.  But heaven has several levels, and the level in which a person resides depends entirely on the care the eldest son gives his parents's spirit after their death.  Ancesors are worshipped by pig sacrifices three times per year.

The Yao in Vietnam are not a completely unreached people group.  Some Yao became believers during the period of French colonization.  Accordingly, they have a measure of official recognition.  The official church is not evangelistic, however.  In recent years, Yao in several areas of northern Vietnam have come to Christ and are being discipled by believers from underground churches.  Far East Broadcasting Company does transmit a program in the Mien language daily.  The New Testament and portions of the Old Testament are available.  But most are printed in a script that few outside of Thailand can read.  A version of the Jesus film for the Yao is now finished.  In China there are at most a few hundred Christian Yao.