Ratnakarashanti (Skt. Ratnākaraśānti; Tib. རིན་ཆེན་འབྱུང་གནས་ཞི་བ་, Wyl. rin chen 'byung gnas zhi ba) was a famous abbot at the great monastic university of Vikramashila in India. Under the name of Shantipa (Skt. Śāntipa), he was also one of the eighty-four mahasiddhas, the great realized masters of the Vajrayana teachings. He was a contemporary and a teacher of Atisha.
Ratnākaraśānti (also known as Śāntipa) (c. 1000 CE) was one of the eighty-four Buddhist Mahāsiddhas and the chief debate-master at the monastic university of Vikramaśīla. At Vikramaśīla he was instructed by Nāropa, and taught both Atiśa and Maitrīpa. His texts include several influential commentaries to Buddhist tantras, as well as works of philosophy and logic.
Little else is known about his life; in the Biography of the Eighty-Four Siddhas, Abhayadhatta records that "King Kapina" invited Ratnākaraśānti to Śrī Laṇka during the reign of the Pāla king Devapāla (c. 810-850 CE). However, according to Keith Dowman, "As history of Śrī Laṇkā the legend is incomprehensible. There is no King Kapina in the lists of Siṇghala kings… [and] there is no evidence of a Śāntipa contemporary with the Pāla Emperor Devapāla." Tāranātha provides a more realistic date, placing him during the reign of King Canaka (955-83 CE).
Ratnākaraśānti composed three commentaries to the Guhyasamāja Tantra, as well as commentaries to the Hevajra Tantra and the Mahāmāyā Tantra. His exoteric works, generally written from a Yogācāra perspective, include several commentaries to the Perfection of Wisdom literature, such as his Sāratamā and Pith Instructions for the Perfection of Wisdom (Prajñāpāramitābhāvanopadeśa). He is also the author of two commentaries to Śāntarakṣita's Madhyamākalaṃkāra, and a technical treatise on the formal logic of pramāṇa theory (the Antarvyāptisamarthana).