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.

The Dalai Lama is a high lama in the Gelug or "Yellow Hat" branch of Tibetan Buddhism. The name is a combination of the Sino-Mongolian word далай (dalai) meaning "Ocean" and the Tibetan word བླ་མ་ bla-ma (with a silent "b") meaning "chief, high priest".

In religious terms, the Dalai Lama is believed by his devotees to be the rebirth of a long line of tulkus who are considered to be manifestations of the bodhisattva of compassion, Avalokiteśvara. Traditionally, the Dalai Lama is thought of as the latest reincarnation of a series of spiritual leaders who have chosen to be reborn in order to enlighten others. The Dalai Lama is often thought to be the leader of the Gelug School, but this position belongs officially to the Ganden Tripa, which is a temporary position appointed by the Dalai Lama who, in practice, exerts much influence. The line of Dalai Lamas began as a lineage of spiritual teachers; the 5th Dalai Lama assumed political authority over Tibet.

For certain periods between the 17th century and 1959, the Dalai Lamas sometimes directed the Tibetan government, which administered portions of Tibet from Lhasa. The 14th Dalai Lama remained the head of state for the Central Tibetan Administration ("Tibetan government in exile") until his retirement on March 14, 2011. He has indicated that the institution of the Dalai Lama may be abolished in the future, and also that the next Dalai Lama may be found outside Tibet and may be female. The Chinese government was very quick to reject this and claimed that only it has the authority to select the next Dalai Lama.