Vajrayāna Buddhism (Devanagari: वज्रयान; Oriya: ବଜ୍ରଯାନ, Tibetan: རྡོ་རྗེ་ཐེག་པ་, rdo rje theg pa; Mongolian: Очирт хөлгөн, Ochirt Hölgön) is also known as Tantric Buddhism, Tantrayāna, Mantrayāna, Secret Mantra, Esoteric Buddhism and the Diamond Vehicle. Vajrayana is a complex and multifaceted system of Buddhist thought and practice which evolved over several centuries.

According to Vajrayana scriptures Vajrayana refers to one of three vehicles or routes to enlightenment, the other two being the Hinayana and Mahayana.

Its main scriptures are called Tantras. A distinctive feature of Vajrayana Buddhism is ritual, which are Skillful Means (Upaya). They are being used as a substitute or alternative for the earlier abstract meditations.

Although the first tantric Buddhist texts appeared in India in the 3rd century and continued to appear until the 12th century, scholars such as Hirakawa Akira believe that the Vajrayana probably came into existence in the 6th or 7th century, while the term Vajrayana first came into evidence in the 8th century. Prior to the Vajrayana developed the Mantrayana, and after the Vajrayana the Sahajayana and Kalachakrayana developed.