The Onkor Festival (Harvest Festival) is one of the most popular and busy festivals in the rural areas of Tibet, except the Losar Festival (Tibetan New Year). In general, Onkor is celebrated at the end of the seventh month on lunar calendar just before peasants begin to reap their crops. According to the agronomic arrangement, the specific dates for the Festival vary according to places.

It is said that the Onkor Festival has enjoyed a history of more than1500 years. According to the relevant Tibetan documents, aqueducts were constructed in the Yalong area at the end of the 5^th century AD, people began to use wooden ploughs to plow, and the agricultural production was comparatively developed. In order to ensure the plenteous harvest, the Tibet King sbu-de-gung-rgyal asked the hierarch of Bon religion for guidance. Following the tenets of Bon religion, the hierarch of Bon religion taught the peasants to walk around their field, beseeching the Heaven for a plenteous harvest, which is the origin of the Onkor. But the Onkor was not a formal festival at that time, only an activity before reaping the crops.

During the late years of the 8^th century, Tibet came to the Silver Age of Tibet Buddhism when the representative sect was the Nyingmapa sect, and the Onkor activity therefore was tinged with the features of the Nyingmapa sect. In the 14^th century, Tsong Khapa, the founder of the Gelugpa sect came to Tibet. Through rectifying various sects of Tibet, the Gelugpa became the main sect in Tibet with dominant authority. More features of the Gelugpa sect were added into the Onkor activities of the time accordingly. Along with the evolution of the time, the contents and forms of the Onkor changed continuously.