The Sarvāstivāda (𑀲𑀩𑁆𑀩𑀢𑁆𑀣𑀺𑀯𑀸𑀤, श्र्वास्तिवाद; ) was one of the early Buddhist schools established around the reign of Ashoka (third century BCE). It was particularly known as an Abhidharma tradition, with a unique set of seven Abhidharma works.
The Sarvāstivādins were one of the most influential Buddhist monastic groups, flourishing throughout North India (especially Kashmir) and Central Asia until the seventh century. The orthodox Kashmiri branch of the school composed the large and encyclopedic Abhidharma Mahāvibhāṣa Śāstra (अभिधर्म महाविभाष शास्त्र) around the time of the reign of Kanishka (c. 127–150 CE). Because of this, orthodox Sarvāstivādins who upheld the doctrines in the Mahāvibhāṣa were called Vaibhāṣikas.
According to the Theravādin Dīpavaṃsa (दीपवंस), the Sarvāstivādins emerged from the older Mahīśāsaka school, but the Śāriputraparipṛcchā (शारिपुत्रपरिपृच्छा) and the Samayabhedoparacanacakra (समयभेदोपरचनचक्र) state that the Mahīśāsaka emerged from the Sarvāstivāda. The Sarvāstivādins are believed to have given rise to the Mūlasarvāstivāda and Sautrāntika schools, although the relationship between these groups has not yet been fully determined.
Sarvāstivāda is a Sanskrit term that can be glossed as: "the theory of all that exists". The Sarvāstivāda argued that all dharmas exist in the past, present and future, the "three times". Vasubandhu's Abhidharmakośa-bhāsya states, "He who affirms the existence of the dharmas of the three time periods [past, present and future] is held to be a Sarvāstivādin."
Although there is some dispute over how the word "Sarvāstivāda" is to be analyzed, the general consensus is that it is to be parsed into three parts: sarva "all" or "every" + asti "exist" + vada "speak", "say" or "theory". This equates perfectly with the Chinese term, Shuōyīqièyǒu bù (), which is literally "the sect that speaks of the existence of everything," as used by Xuanzang and other translators.
The Sarvāstivāda was also known by other names, particularly hetuvada and yuktivada.