The Hare Krishna mantra, reverentially known as the Mahā-mantra (Great Mantra), is a sixteen-word Vaishnava Hindu mantra mentioned in the Kali-Santāraṇa Upaniṣad. It is composed of three Sanskrit names — "Krishna", "Rama", and "Hare" — repeated in a set sequence. Within the Vaishnava tradition, the chanting of these names is regarded as a central devotional practice.
The mantra rose to particular importance in the 15th century during the Bhakti movement, following the teachings of Chaitanya Mahaprabhu. In the Gaudiya Vaishnava tradition associated with Chaitanya, the congregational and individual chanting of the names of Krishna is considered a principal means of devotion in the present age.
From the 1960s onwards, the mantra became widely known outside India through the work of A. C. Bhaktivedanta Swami Prabhupada and the movement he founded, the International Society for Krishna Consciousness (ISKCON), commonly referred to as the Hare Krishnas or the Hare Krishna movement. Through this movement, public chanting of the mantra has become a recognisable feature of Vaishnava devotional practice in many parts of the world.