'Hayagriva (also Hayagreeva; Sanskrit: Hayagrīva) is a horse-headed avatar of the god Vishnu in Hinduism.

In Hinduism, Hayagrīva is also considered an Avatar of Vishnu. He is worshiped as the God of knowledge and wisdom, with a human body and a horse's head, brilliant white in color, with white garments and seated on a white lotus. Symbolically, the story represents the triumph of pure knowledge, guided by the hand of God, over the demonic forces of passion and darkness.

Hayagrīva is a very important deity in the Vaishnava tradition. His blessings are sought when beginning study of both sacred and secular subjects. Special worship is conducted on the day of the full moon in August (Śravaṇa-Paurṇamī) (his avatāra-dina) and on Mahanavami, the ninth day of the Navaratri festival. He is also hailed as "Hayasirsa". Hayaśirṣa means haya=Horse, śirṣa=Head.

In IAST
jñānānanda mayaṃ devaṃ nirmala sphaṭikākṛtiṃ
ādhāraṃ sarvavidyānaṃ hayagrīvaṃ upāsmahe

In Devanāgarī
ज्ञानानन्द मयं देवं निर्मल स्फटिकाकृतिं
आधारं सर्वविद्यानं हयग्रीवं उपास्महे