Spreading of Buddhism from Nalanda University made a great epoch in early India for the sake of Buddhism. Traditional Indian ancient texts state that Nalanda was visited by both Lord Mahavira and Gautama Buddha in 6th and 5th century BC. Other Chinese and Korean travellers like Hiuen Tsang, Fahien and Yinjang also spread Buddhism in the early era.

Tibetan Buddhism in Nalanda
A vast amount of Tibetan Buddhism, both its Mahayana and Vajrayana traditions, stems from the teachers and traditions at Nalanda. Shantarakshita, who pioneered the propagation of Buddhism in Tibet in the 8th century, was a scholar of Nalanda. He was invited by the Tibetan king, Khri-sron-deu-tsan, and established the monastery at Samye, serving as its first abbot. He and his disciple Kamalashila (who was also of Nalanda) essentially taught Tibetans how to do philosophy. Padmasambhava, who was also invited from Nalanda Mahavihara by the king in 747 CE, is credited as a founder of Tibetan Buddhism.

Philosophy of Buddhism Spread from Nalanda
The scholar Dharmakirti one of the Buddhist founders of Indian philosophical logic, as well as one of the primary theorists of Buddhist atomism, taught at Nalanda.

Expansion of Mahanayana Buddhism from Nalanda
Other forms of Buddhism, such as the Mahayana Buddhism followed in Vietnam, China, Korea and Japan, flourished within the walls of the ancient school. A number of scholars have associated some Mahayana texts such as the Shurangama Sutra, an important sutra in East Asian Buddhism, with the Buddhist tradition at Nalanda. Historians also note that the general doctrinal position of the sutra does indeed correspond to what is known about the Buddhist teachings at Nalanda toward the end of the Gupta period when it was translated.

Account of Hiuen Tsang on Nalanda
Hiuen Tsang was a contemporary and an esteemed guest of Nalanda and Harshavardhana and catalogued the emperor`s munificence in some detail. According to Hiuen Tsang, Nalanda was held in contempt by some Sthaviras for its emphasis on Mahayana philosophy. They reportedly chided King Harsha for patronising Nalanda during one of his visits to Odisha, mocking the "sky-flower" philosophy taught there and suggesting that he might as well patronise a Kapalika temple. When this occurred, Harshavardhana, notified the Chancellor of Nalanda, who sent the monks Sagaramati, Prajnyarashmi, Simharashmi, and Hiuen Tsang to contest the views of the monks from Odisha, which spread to Bengal (now West Bengal).