A later-developing school of Buddhism, originating in India, and having extensive influence in Tibet, as well as considerable influence in China and Japan, but less in Korea. The hallmark of the school was a reliance on mystical formulas called mantra and dhāraṇī 陀羅尼. As the school developed, scriptures were written which focused on esoteric practices such as these. The term tantrayāna is applied due to the fact that the school was based on texts called tantras. Mantrayāna refers to the usage of chants and dhāraṇīs, while vajrayāna refers to the dominant symbol of the school, the vajra, translated variously as 'thunderbolt,' 'diamond' and 'cudgel.' The school developed its system of philosophy borrowing from Madhyamaka 中觀派 and Yogâcāra 瑜伽行派.

Though admitting the emptiness of all phenomena, practitioners believe that the phenomenal world is not to be disregarded but to be looked upon as a vehicle for progress toward liberation. Developing in India during the seventh and eight centuries under the influence of ritualistic Hinduism, it was transmitted into China during the Tang dynasty by Śubhakarasiṃha, Vajrabodhi 菩提金剛 and Amoghavajra 不空金剛. In Japan, the esoteric teachings were systemized into Shingon 眞言宗 and Tendai 天台宗. For a study of this school in China, see Chou (1945).