Mahavatar Babaji (IAST: Mahāvatāra Bābājī; lit. 'Great Avatar (Revered) Father') is a legendary immortal yogi and guru, who is said to be living in the Himalayas. He is said to have taught multiple revered historic yogis, including Lahiri Mahasaya (1828–1895). Babaji first became recognised through the writings of Paramahansa Yogananda, who devoted a chapter of his Autobiography of a Yogi to Babaji and founded Self-Realization Fellowship, a modern yoga movement that Babaji is associated with. The cave where Babaji met Lahiri Mahasaya, located near Ranikhet, is now a tourist attraction and place of pilgrimage in India.
There is little historical information about Babaji. According to Yogananda, Babaji has intentionally kept his birthplace and birthdate a secret.