Vasishtha (वसिष्ठ, IAST: ) is one of the oldest and most revered Vedic rishis or sages, and one of the Saptarishis (seven great Rishis). Vashistha is credited as the chief author of Mandala 7 of the Rigveda. Vashishtha and his family are mentioned in Rigvedic verse 10.167.4, other Rigvedic mandalas and in many Vedic texts. His ideas have been influential and he was called the first sage of the Vedanta school of Hindu philosophy by Adi Shankara.
The Yoga Vasishtha, Vasishtha Samhita, as well as some versions of the Agni Purana and Vishnu Purana are attributed to him. He is the subject of many stories, such as him being in possession of the divine cow Kamadhenu and Nandini her child, who could grant anything to their owners. He is famous in Hindu stories for his legendary conflicts with sage Vishvamitra. In the Ramayana, he was the family priest of the Raghu dynasty and teacher of Rama and his brothers.
Vasishtha is also spelled as and is Sanskrit for "most excellent", "best" or "richest". According to Monier-Williams, it is sometimes alternatively spelt as Vashishta or Vashisht (, वशिष्ठ).
Historically, Vasishtha was a Rigvedic poet and the purohita of Sudās Paijavana, chief of the Bharata tribe. In Rigvedic hymn 7.33.9, Vashishtha is described as a scholar who moved across the Saraswati river to establish his school. At some point, he replaced Viśvāmitra Gāthina as the purohita of Sudās. In later Hindu texts, Viśvāmitra and Vasiṣṭha have a long-standing feud, and scholars have stated they historically had a feud regarding the position of the Bharata purohita. However, this view has been criticized due to lack of internal evidence and the projection of later views onto the Rigveda. Under Sudās and Vasiṣṭha, the Tṛtsu-Bharatas won the Battle of the Ten Kings. Sudās decisively won against a Puru-led alliance by the strategic breaching of a (natural) dyke on the Ravi river thereby drowning most of the opponents; the victory is attributed to the benevolence and strategizing of Indra, the patron-god of the Bharatas, whose blessings were secured by Vasistha's poetics.