Yajnavalkya (Sanskrit: याज्ञवल्क्य, Yājñavalkya) is a Hindu Vedic sage. He is mentioned in the Upanishads, and likely lived in the Videha kingdom of northern Bihar approximately between the 8th century BCE,and the 7th century BCE Yajnavalkya is considered one of the earliest philosophers in recorded history, after Aruni. Yajnavalkya proposes and debates metaphysical questions about the nature of existence and impermanence, and expounds the epistemic doctrine of neti neti ("not this, not this") to discover the universal Self and Ātman. His ideas for renunciation of worldly attachments have been important to Hindu sannyasa traditions.
Yajnavalkya is credited for coining Advaita (non-dual, monism), another important tradition within Hinduism. Texts attributed to him, include the Yajnavalkya Smriti, Yoga Yajnavalkya and some texts of the Vedanta school.He is also mentioned in various Brahmanas and Aranyakas.
He welcomed participation of women in Vedic studies, and Hindu texts contain his dialogues with two women, Gargi Vachaknavi and Maitreyi.
Yajnavalkya is associated with several other major ancient texts in Sanskrit, namely the Shukla Yajurveda, the Shatapatha Brahmana, the Brihadaranyaka Upanishad, the Dharmasastra named Yājñavalkya Smṛti, Vriddha Yajnavalkya, and Brihad Yajnavalkya. He is also mentioned in the Mahabharata and the Puranas, as well as in ancient Jainism texts such as the Isibhasiyaim.
Another important and influential Yoga text in Hinduism is named after him, namely Yoga Yajnavalkya, but its author is unclear. The actual author of Yoga Yajnavalkya text was probably someone who lived many centuries after the Vedic sage Yajnavalkya, and is unknown. Ian Whicher, a professor of Religion at the University of Manitoba, states that the author of Yoga Yajnavalkya may be an ancient Yajnavalkya, but this Yajnavalkya is not to be confused with the Vedic-era Yajnavalkya "who is revered in Hinduism for Brihadaranyaka Upanishad".
According to Vishwanath Narayan Mandlik, these references to Yajnavalkya in other texts, in addition to the eponymous Yoga Yajnavalkya, may be to different sages with the same name.