Awasthi is a surname / family name of a particular sub-caste of Brahmins of India.

For last several centuries, Awasthi Brahmins are located in and around Kanpur and Unnao (and the adjoining hinterland) located in the fertile Gangetic plains of Awadh, presently forming part of the state of Uttar Pradesh, India. The geographical area, where majority of Awasthi families are presently located, for last several centuries, has a rich mythological and historical heritage and is a crystal ball of ancient as well as the modern Indian civilization.

There exists no credible source of information as regards the period since when the Awasthi Brahmins have been residing in Awadh area. There is also no complete and authoritative count of Brahmin sub-castes (or any other castes / sub-castes) in India. For example, Rev. M.A. Sherring in the 1860s, had compiled names of about 2,000 sub-castes of Brahmins in his second volume of his Hindu Tribes and Castes. And, he had indicated that the list could be incomplete.

According to studies conducted by Rev. M A Sherring, all the chief Brahmin gotras are descended from the Saptarishis (sapta means seven and rishiss means sages in Sanskrit). The other meaning of Saptarishis is constellation of Great Bear (Ursa Major).

According to Indian mythology, these seven sages were Brigu, Angirh, Atri, Viswamitra, Kashyap, Vashisht, and Agastya. Awasthi Brahmins belong to sage Upamanyus Gotra, and sage Upamanyus, along with sages like Vishisht, Kundin, Parashara and Jatukaraniya followed the school of (thought) of sage Vashisht. Mythological evidences suggest that the Sage Upamanyus followed the Yajur veda. From the ancient time of the vedic period, Awasthi Brahmins have always excelled in intellectual pursuits and they still continue to excel in activities requiring brains than the brawns. In Brahmin hierarchical level, they are like Shukla and Vajpayee Brahmins.

Being residing in the ancient land of Awadh and their gotra being Upamanyus, who was indoctrinated in the school (of thought) of sage Vashist, the surname Awasthi is likely to be a shortened "Awadhi" form and derivative of “Awadh-Vashist”.

The mother tongue of Awasthi Brahmins is Awadhi, an Indo-Aryan language, akin to Hindi. Awadhi is the language, in which, the famed epic Ramcharitamanasa was written by Tulasi Das. Like most of the north Indian Brahmins, Awasthi Brahmins donot allow consanguineous marriages, which are in vogue in some social groups in other parts of India.

Although most of Awasthi Brahmins are confined in the area of Awadh, with the changing time they are moving out to other areas, and out of their “home zone” of Awadh, they are, sometimes, mistaken to belong to Kayastha caste, which have some similar sounding surnames like Asthana and Ambastha.