Navayāna (Devanagari: नवयान, IAST: Navayāna, meaning "New Vehicle"), otherwise known as Navayāna Buddhism, refers to the socially engaged school of Buddhism founded and developed by the Indian jurist, social reformer, and scholar B. R. Ambedkar; it is also called Neo-Buddhism and Ambedkarite Buddhism. Its members describe the school as the application of Buddhist principles for the welfare of many.

Ambedkar was an Indian lawyer, politician, and scholar of Buddhism, and the Drafting Chairman of the Constitution of India. He was born in an untouchable family during the colonial era of India, studied abroad, became a Dalit leader, and announced in 1935 his intent to convert from Hinduism to a different religion, an endeavor which took him to study all the major religions of the world in depth, namely Hinduism, Buddhism, Sikhism, Christianity, and Islam, for nearly 21 years. The school was otherwise named Ambedkarite Buddhism after him by people after his death. Ambedkar held a conference on 13 October 1956, announcing his rejection of Hinduism. Thereafter, he left Hinduism and adopted Buddhism as his religious faith, about six weeks before his death. Its adherents see Navayāna Buddhism not as a sect with radically different ideas, but rather as a new social movement founded on the principles of Buddhism.

In the Buddhist faith, Navayāna is not considered as an independent new branch of Buddhism native to India, distinct from the traditionally recognized branches of Theravāda, Mahāyāna, and Vajrayāna—considered to be foundational in the Buddhist tradition. It radically re-interprets what Buddhism is; Ambedkar regarded Buddhism to be a better alternative than Marxism or Communism, taking into account modern problems within Indian society.

While the term Navayāna is most commonly used in reference to the movement that Ambedkar founded in India, it is also (more rarely) used in a different sense, to refer to Westernized forms of Buddhism. Ambedkar called his version of Buddhism Navayāna or "Neo-Buddhism". His book, The Buddha and His Dhamma, is considered the primary doctrine of Buddhism by Navyana Buddhists. The followers of Navayāna Buddhism are generally called "Buddhists" (Bauddha) as well as Ambedkarite Buddhists, Neo-Buddhists, and rarely Navayāna Buddhists. Almost 90% of Navayāna Buddhists live in Maharashtra.

Ambedkar was an Indian leader influential during the colonial era and early post-independence period of India. He was the fourteenth child in an impoverished Maharashtra Schedule caste family, who studied abroad, returned to India in the 1920s and joined the political movement. His focus was social and political rights for the Depressed class community. To free his community from religious prejudice, he concluded that they must leave Hinduism and convert to a different religion. He chose Buddhism as the only way to end human suffering.

In 1935, following disagreements with Mahatma Gandhi, Ambedkar announced his intent to convert from Hinduism to Buddhism. Over the next two decades, Ambedkar studied Buddhist texts and wrote The Buddha and His Dhamma which is considered the primary doctrine of those who follow Navayana Buddhism.

Ambedkar re-emphasized Buddhist principles to address modern issues. Navayana dhamma doctrine as propounded by Ambedkar, states Sumant (2004), "does not situate morality in a transcendental [religious] domain", nor in "a civil association, including the state". Dhamma is derived from and the guiding principle for social conscience.

Navayana Buddhism began in 1956, when Bhimrao R. Ambedkar adopted it, and 380,000 oppressed community members converted to Navayana Buddhism from Hinduism on 14 and 15 October 1956. After that on every year 14 October is celebrated as Dhammachakra Pravartan Day at Dikshabhoomi, Nagpur: