Sthavira Nikāya in the context of "Second Buddhist Council"

The Mahāsāṃghika (Brahmi: 𑀫𑀳𑀸𑀲𑀸𑀁𑀖𑀺𑀓, "of the Great Sangha", Chinese: 大眾部; pinyin: Dà zhòng bù; Vietnamese: Đại chúng bộ) was a major division (Nikāya) of the early Buddhist schools in India. They were one of the two original communities that emerged from the first schism of the original pre-sectarian Buddhist tradition (the other being the Sthavira Nikāya). This schism is traditionally held to have occurred after the Second Buddhist council, which occurred at some point during or after the reign of Kalashoka. The Mahāsāṃghika Nikāya developed into numerous sects which spread throughout ancient India.

Some scholars think that the Mahāsāṃghika Vinaya (monastic rule) represents the oldest Buddhist monastic source, although some other scholars think that it is not the case. While the Mahāsāṃghika tradition is no longer in existence, many scholars look to the Mahāsāṃghika tradition as an early source for some ideas that were later adopted by Mahāyāna Buddhism. Some of these ideas include the view that the Buddha was a fully transcendent being (term "lokottaravāda", "transcendentalism"), the idea that there are many contemporaneous buddhas and bodhisattvas throughout the universe, the doctrine of the inherent purity and luminosity of the mind (Skt: prakṛtiś ćittasya prabhāsvarā), the doctrine of reflexive awareness (svasaṃvedana) and the doctrine of prajñapti-matra (absolute nominalism or pure conceptualism).

The early Buddhist schools refers to the Indian Buddhist "doctrinal schools" or "schools of thought" (Sanskrit: vāda) which arose out of the early unified Buddhist monastic community (Saṅgha) due to various schisms in the history of Indian Buddhism. The various splits and divisions were caused by differences in interpretations of the monastic rule (Vinaya), doctrinal differences and also due to simple geographical separation as Buddhism spread throughout the Indian subcontinent.

The early Buddhist community initially split into two main Nikāyas (monastic groups, divisions): the Sthavira ("Elders"), and the Mahāsāṃghika ("Great Community"). This initial split occurred either during the reign of Aśoka (c. 268-232 BCE) or shortly after (historians disagree on the matter).

The Pudgalavāda (Sanskrit: "Personalism"; Pali: Puggalavāda; Chinese: 補特伽羅論者; pinyin: Bǔtèjiāluō Lùnzhě; Vietnamese: Bổ-đặc-già-la Luận giả) was a Buddhist philosophical view and also refers to a group of Nikāya Buddhist schools (mainly known as Vātsīputrīyas) that arose from the Sthavira Nikāya. The school is believed to have been founded by the elder Vātsīputra in the third century BCE. They were a widely influential school in India and became particularly popular during the reign of emperor Harshavadana (606–647 CE). Harsha's sister Rajyasri was said to have joined the school as a nun. According to Dan Lusthaus, they were "one of the most popular mainstream Buddhist sects in India for more than a thousand years".

Vibhajyavāda (Sanskrit; Pali: Vibhajjavāda; traditional Chinese: 分別說部; ; pinyin: Fēnbiéshuō Bù; Vietnamese: Phân biệt thuyết bộ, Phân tích bộ) is a term applied generally to groups of early Buddhists belonging to the Sthavira Nikāya, which split from the Mahāsāṃghika (due either to the former attempting to make the Vinaya stricter, or the latter wishing to reform it; see: Sthavira Nikāya main article) into two main groups: the Sarvāstivāda and the Vibhajyavāda, of which the latter are known to have rejected both Sarvāstivāda doctrines (especially the doctrine of "all exists") and the doctrine of Pudgalavāda (personalism). During the reign of Ashoka, these groups possibly took part in missionary activity in Gandhara, Bactria, Kashmir, South India and Sri Lanka. By the third century CE, they had spread in Central Asia and Southeast Asia. Their doctrine is expounded in the Kathāvatthu.