Nikaya Buddhism is a general term for those schools of Buddhism that accept only the class of sutras collected in the Pāli Canon as authentic. Historically, there were many Nikaya schools, but only one still exists today: the Theravada.

The division of schools of Buddhism originates from a series of councils held after the death of the Buddha. The first Buddhist council was held soon after the death of the Buddha. Its objective was to record the Buddha's sayings (sutra) and codify monastic rules (vinaya). In the second Buddhist council, the dispute arose about the matter of adherence to monastic rules (vinaya). A conservative group known as Sthaviravada insisted on strict observation of vinaya. A more liberal group known as Mahasangikas argued that some minor rules could be relaxed. The council ended with the rejection of the Mahasanghikas. In time, up to 18 schools arose out of these disputes and Nikaya refers to these schools or to this period of Buddhism. The third Buddhist council was convened by the Mauryan king Ashoka (260-218 BC). Its objective was to reconcile the different schools of Buddhism as well as to stamp out heresy. Tipitaka (or Tripitaka in Sanskrit, lit. the "Three Baskets") was formalized at this time. It consisted of the doctrine (the Sutra Pitaka), the monastic discipline (Vinaya Pitaka) and an additional new body of subtle philosophy (the Abhidharma Pitaka). According to Theravadan, one of the Nikaya schools, Sarvastivadin were rejected by the 3rd council.

Nikaya Buddhism is distinguished from the Buddhism of the various Mahayana and Vajrayana schools, which accept the authenticity of a range of other scriptures. However, the sutras of Pali Canon are accepted by every school, and outside Nikaya Buddhism they are known as the agamas or Nikayas. The Nikaya schools have traditionally been identified by Western scholars as Hinayana schools. However, this terminology is now often seen as flawed on two levels. First, Hinayana, literally "inferior vehicle", is often regarded as a offensive or pejorative term coined by the Mahayana school and is not used by the Nikaya (Theravadan) school. Second, in Mahayana and subsequent Vajrayana doctrine, 'Hinayana' refers to two of three classes/paths of liberation, that is Shravakayana (the hearer vehicle) and Pratyekayana (the solitary vehicle) as opposed to Bodhisattvayana (The Bodhisattva vehicle). This is not in accordance with the definition of Nikaya which is primarily a term of historical reference to the collection of schools.

Currently, "Nikaya" is often used in place of "Hinayana" in an attempt to find a more neutral term. However, "Nikaya" only refers to a collection of schools and does not have the other meanings of "Hinayana."

See also: early Buddhist schools.