Synopsis This title is a historical analysis of origin and development of Buddhist sects and sectarianism in the history of the succession of schools, it is found that the first schism in the sangha was followed by a series of schisms leading to the formation of different sub-sects, and in the course of time eleven such sub-sects arose out of the Theravada while seven issued from the Mahasasnghikas. All these branches of Buddhist sects appeared one after another in close succession which in three or four hundred years after the Buddha's parinirvana. Here, we focus on following important aspects: growth and ramification of Buddhist sects and sectarian schools; Mahayana Buddhism, Theravada Buddhism, Tantric Buddhism, Yogacara, Newar Buddhism, Bhutanese Buddhist sects, Protestant Buddhism, Nichren Buddhism, Amida Buddhism, Tendai Buddhism, Shingon Buddhism, Zen Buddhism, Millennial Buddhism. There are different authorities, such as the traditions of the Theravadins, Sammitiyas, Mahasanghikas, and subsequently the Tibetan and Chinese translations which give us accounts of the origin of the different sects and sectarianism.