The Saṃmitīya (Sanskrit; Chinese: 正量部; pinyin: Zhèngliàng Bù) were one of the eighteen or twenty early Buddhist schools in India, and were an offshoot of the Vātsīputrīya sect. Like its predecessor, it claims the person (Sanskrit: pudgala) as a carrier of skandhas endures, and as such was a representative (perhaps the most prominent one) of the Pudgalavāda schools.
The Tibetan historian Buton Rinchen Drub wrote that the Mahāsāṃghikas used Prākrit, the Sarvāstivādins used Sanskrit, the Sthaviravāda used Paiśācī, and the Saṃmitīya used Apabhraṃśa.
The distinguished Buddhologist Étienne Lamotte, using the writings of the Chinese traveler Xuanzang, asserted that the Saṃmitīya were in all likelihood the most populous non-Mahāyāna sect in India, comprising double the number of the next largest sect, although scholar L. S. Cousins revised his estimate down to a quarter of all non-Mahāyāna monks, still the largest overall. The Saṃmitīya sect seems to have been particularly strong in the Sindh, where one scholar estimates 350 Buddhist monasteries were Saṃmitīya of a total of 450. This area was rapidly Islamized in the wake of the Arab conquest.
The end of the Saṃmitīya sect appears to coincide with the overall decline of Buddhism in India.