An authentic lineage in Buddhism is the uninterrupted transmission of the Buddha's Dharma from teacher to disciple. The transmission itself can be for example oral, scriptural, through signs, or directly from one mind to another. Several branches of Buddhism, including Zen and Tibetan Buddhism maintain records of their historical teachers. These records serve as a validation for the living exponents of the tradition.

In the lineage of the vinaya, the requirements for ordination as a monk or a nun include the presence of at least five other monks, one of whom must be a fully ordained preceptor, and another an acharya (teacher). This lineage for ordaining nuns became extinct in many Buddhist countries. When Ani Tenzin Palmo wanted full ordination for example, she had to travel to Hong Kong to receive it. Lineages in the Mahasiddha tradition do not necessarily originate from the historical Gautama Buddha, but are ultimately grounded, like all Buddhist lineages, in the primordial Dharmakaya Buddha.

Lineage may refer to:

Buddhism is a religion and philosophy indigenous to the Indian subcontinent and encompasses a variety of traditions, beliefs, and practices largely based on teachings attributed to Siddhartha Gautama, who is commonly known as the Buddha (meaning "the awakened one" in Sanskrit and Pāli). The Buddha lived and taught in the eastern part of Indian subcontinent some time between the 6th and 4th centuries BCE. He is recognized by Buddhists as an awakened or enlightened teacher who shared his insights to help sentient beings end ignorance (avidyā), craving (taṇhā), and suffering (dukkha), by recognizing dependent origination and sunyata, and attain Nirvana.

Two major branches of Buddhism are recognized: Theravada ("The School of the Elders") and Mahayana ("The Great Vehicle"). Theravada has a widespread following in Sri Lanka and Southeast Asia. Mahayana is found throughout East Asia and includes the traditions of Pure Land, Zen, Nichiren Buddhism, Tibetan Buddhism, Shingon, Tiantai (Tendai) and Shinnyo-en. In some classifications, Vajrayana—practiced mainly in Tibet and Mongolia, and adjacent parts of China and Russia—is recognized as a third branch, while others classify it as a part of Mahayana. There are other categorisations of these three Vehicles or Yanas.

Lama Ole Nydahl (born March 19, 1941) is a Danish Lama in the Karma Kagyu school of Tibetan Buddhism under guidance of Trinley Thaye Dorje. Since the early 1970s, Nydahl has toured the world giving lectures and meditation courses. With his wife, Hannah Nydahl, he founded Diamond Way Buddhism, a worldwide lay organization of Karma Kagyu Buddhism.

Nydahl is the author of nine books in English, including The Way Things Are, Entering the Diamond Way, and Riding the Tiger.

Ole Nydahl was born in Copenhagen and grew up in Denmark. In the early 1960s, he served briefly in the Danish Army, then studied philosophy, English, and German at the University of Copenhagen, where he completed the examen philosophicum with the best possible grade. He began but did not finish a doctoral thesis on Aldous Huxley’s Doors of Perception. As a young man, Nydahl was involved in boxing, race car driving and also travelled overland from Denmark to Nepal several times. As described in his book "Entering the Diamond Way", his travels were financed through smuggling, for which he was once arrested and detained in Denmark.