Buddhism is a religion or spiritual philosophy encompassing a variety of traditions, beliefs and practices, largely based on teachings attributed to Siddhartha Gautama, commonly known as the Buddha (Pali/Sanskrit "the awakened one"). Adherents recognize the Buddha as an awakened teacher who shared his insights to help sentient beings end suffering, achieve nirvana, and escape what is seen as a cycle of suffering and rebirth. However, Buddhist schools disagree over the historical teachings of the Buddha, and on the importance and canonicity of various scriptures.

Two major branches of Buddhism are recognized: Theravada ("The School of the Elders") and Mahayana ("The Great Vehicle"). Theravada, the oldest surviving, has a widespread following in Sri Lanka and Southeast Asia, whilst Mahayana, which is found throughout East Asia, includes the traditions of Pure Land, Zen, Nichiren Buddhism, Tibetan Buddhism, Shingon, Tendai and Shinnyo-en. In some classifications, a third branch, Vajrayana, is recognized, although many see this as an offshoot of the Mahayana. Other movements have appeared in recent times, sometimes classified as Buddhist modernism.

While Buddhism remains most popular within Asia, both branches are now found throughout the world. Various sources put the number of Buddhists in the world at between 230 million and 500 million.

The foundation of all Buddhist practice is ethical conduct and altruism. Further practices can vary widely, but may include renunciation, meditation, the cultivation of mindfulness and wisdom, the study of scriptures, physical exercises, devotion and ceremonies, or the invocation of bodhisattvas