Ratnākaraśānti (also known as Ratnākara, Śāntipa, and Śānti) (late-10th century to mid-11th century) was an influential Buddhist philosopher and vajrayana tantric adept and scholar. He was the "gate scholar" of Vikramaśilā university's eastern gate (modern-day Bihar in India), a key post in the university's leadership. Ratnākara was known by the title kalikālasarvajña ("the Omniscient One of the Degenerate Age") and is depicted as one of the eighty-four mahāsiddhas (great yogic masters).
Ratnākara wrote over forty works which include several influential commentaries to Mahayana sutras and tantras (especially the Hevajra tantra), treatises on Yogācāra, Madhyamaka, and Pramāṇa. Because his unique philosophy attempts to merge the insights of both Yogācāra and Madhyamaka, Ratnākara referred to it as Trisvabhāva-mādhyamaka ("the middle way of the three natures"). He also known as a major defender of the "nirākāravāda" (without images") interpretation of Yogācāra.
At Vikramaśilā, Ratnākara was a teacher to Atīśa, Maitrīpa, Śraddhākaravarman, and Drokmi Śākya Yeshe. Ratnākaraśānti was influential on some Tibetan Buddhist figures. Defenders of the shentong view see him as a forerunner of this tradition and as a defender of shentong. His work on the Hevajra Tantra was also influential.
There is much uncertainty about the facts of Ratnākaraśānti's life, since Tibetan and Sanskrit sources disagree on many issues.
Abhayadatta Sri places him during the reign of the Pāla king Devapāla (c. 810-850 CE). However, modern scholars have now determined that the most likely dating for Ratnākaraśānti's birth (based on philological, philosophical and biographical evidence) is in the late tenth century, "slightly before Jñānaśrīmitra, Ratnakīrti, and Adhīśa." Tāranātha says that he took his post at Vikramaśīla during reign of King Canaka (active in the early 11th century).
Naktso Lotsāwa Tsultrim Gyelwa, a Tibetan student of Ratnākaraśānti, states that Ratnākaraśānti was a student of *Dharmakīrtiśrī (a.k.a. Bla ma Gser ling pa, *Dharmakīrti of Suvarṇadvīpa).