Uddalaka Aruni is the Rishi of Atherva Veda Sukta 6:15. Uddalak muni was more known for the Ashram he ran where famous philosophers like Yajnavalkya, Astavakra, Nachiketu and Shwetaketu were brought up. He was a disciple of Rishi Dhaumya and grant son of Bajshrava. Nachiketu and Shwetaketu are his sons. He also had a daughter named Sujata. Sujata was married to his disciple Kahoda and had the son Astavakra.

His real name was Aruni. There is story about him on how he was called as Uddalaka by his Guru, Ayoda-Dhaumya. Ayoda-Dhaumya had three disciples, Upamanyu, Aruni, and Veda. Once there was heavy rain and the Rishi sent Aruni of Panchala, to go and stop up a breach in the water-course of a certain field. Having gone there Aruni saw that he could not stop up the breach in the water-course by ordinary means. So he went down into the breach and lay down himself there. The water was thus confined and crop protected. After sometimes Sage Dhaumya went to field along with other two other disciples in search of Aruni who don’t returned from field. They found Aruni in very pathetic condition in the watercourse. The Sage pleased by the commitment of the student named him as Uddalaka.