The religions in Mongolia are varied, since the creation of the great Turco-Mongol empires and during their more than 1500 years of existence, due to the diversity of the confessions of the dominated populations. Under the term Mongolia, we can group together several territorial entities: Mongolia as it was at the time of the Mongol Empire, covering most of Asia and beyond, or the different parts of Greater Mongolia , what is today the Mongol State (Mongolian Cyrillic: монгол улс, Mongol uls), semi-independent under the Mongolian Khanate of Bogd (1912-1924) and officially independent since 1921; Inner Mongolia, which remained in Chinese territory; and the various other regions of the world of Mongolian culture. Tengrism (a form of shamanism), already present among the Xiongnu, remains the basis of the organization in the steppes of Central Asia, opposed or mixed by syncretism with different major religions (Buddhism, Christianity, Islam). In the independent Mongolian state, Buddhism is the majority, practiced by just over 53% of the population. It is followed by irreligion, claimed by approximately 38% of the population. Finally, Islam and shamanism, with 3% of practitioners each, slightly ahead of Christianity with 2.1% of practitioners. The school of yellow caps (gelugpa) is the majority Buddhist doctrine in Mongolian country. Buddhism and shamanism are actually intertwined in what is called yellow shamanism where shamanic practices are linked to Buddhist rites. In certain regions of the former Mongol Empire where strong Mongol populations remain, the majority practice is Islam. Currently, in Mongolia as in Inner Mongolia, Buddhism, Islam (mainly in the regions inhabited by the Khazaks) and Christianity are still practiced, with however other local religions, with additions by syncretism of elements of Tengrism , an ancient religion linked to the foundations of the Empire and the power of Genghis Khan.

The communists accepted under the banner of the Mongolian People's Party, during the last years of autonomous Mongolia (1911-1924), Buddhism between 1921 and 1924, putting the theocrat Bogdo Khan back on the throne. On the latter's death, the establishment of the Mongolian People's Republic (1924-1992) was declared and the country officially became secular. Tengrism has however always remained present, at least as a superstition, in the minds of the populations and mainly among the nomads. In November 1993, one year after the proclamation of the Republic of Mongolia, a law on religions imposes Buddhism as the state religion and prohibits any religious activity organized from outside without government invitation. Despite decades of state atheism, Tibetan Buddhism remains the main religion of the Mongols in Inner Mongolia and Mongolia: practitioners consider the 14th Dalai Lama to be one of their spiritual leaders.