The Kadampa tradition founded by Atisha was the direct source of inspiration for the development of the Gelugpa tradition founded by Je Tsong Khapa (1357-1419).

Je Tsong Khapa was born in the Tsongkha region of Amdo province. At the age of 3 he received full-fledged lay ordination from the 4th Karmapa, Rolpey Dorje, and the name Kunga Nyingpo. At the age of 7 he received novice vows from his teacher, Choje Dhondup Rinchen, and was given the name Lobsang Drakpa. Even at this young age he had received many teachings and initiations of Heruka, Yamantaka and Hevajra, and could recite by heart texts like 'Expression of the Names of Manjushri'.

Tsong Khapa traveled extensively in search of knowledge and studied with masters of all the existing traditions beginning with Chennga Choyi Gyelpo, from whom he received teachings on topics such as the mind of enlightenment and the Great Seal (Mahamudra). He was taught the medical treatises by Kechok Kyab at Drikung. In Nyethang Dewachen he studied the Ornaments for clear Realization and the Perfection of Wisdom and, excelling in debate, he became famous for his erudition. He also traveled to Sakya where he studied monastic discipline, phenomenology, valid cognition, the Middle Way and Guhyasamaja with lamas such as Kazhipa Losel and Rendawa. He also received transmissions of the 6 Yogas of Naropa, the Kalachakra, Mahamudra, the Lam-Dre teachings, Chakrasamvara and numerous others and transmitted them to his disciples.

In addition to his studies and teachings he engaged in extensive meditation retreats. The longest, at Wolkha Cholung, lasted four years during which he was accompanied by eight close disciples. He is reputed to have performed millions of prostrations, mandala offerings and other forms of purification practice. Tsong Khapa frequently had visions of meditational deities and especially of Manjushri, with whom he could communicate to settle his questions about profound aspects of the teachings.

Tsong Khapa studied with more than a hundred teachers, practiced extensively and taught thousands of disciples mainly in the central and eastern regions of Tibet. In addition he wrote a great deal. His collected works, comprising eighteen large volumes, contain hundred of titles relating to all aspects of Buddhist teachings and clarify some of the most difficult topics of sutra and tantra teachings. Major works among them are: The Great Exposition of the Stages of the Path (Lam-rim Chen-mo), The Great Exposition of Tantras (Ngag-rim Chenmo), The Essence of Eloquence on the Interpretive and Definitive Teachings (Drnng-nges legs-bshad snying-po), The Praise of Relativity (rTen-'brelbstodpa), The Clear Exposition of the Five Stages of Guhyasamaja (gSang-'dus rim-lngagsal-sgron) and The Golden Rosary (gSer-phreng). Among his many main disciples, Gyeltsab Dharma Rinchen, Khedrub Geleg Pelsang, Gyalwa Gendun Drup, Jamyang Choje Tashi Pelden, Jamchen Choje Sakya Yeshe, Je Sherab Sengey, Tsako Ngawang Drakpa and Kunga Dhondup are some of the more significant.

Tsong Khapa passed away at the age of 60 on the 25th of the 10th Tibetan month, entrusting his throne in Gadan to Gyeltsab Je. So began a tradition known as the Gelugpa Lineage (also known as the Gadan Tradition) which continues to the present day.

Of the major Gelugpa monasteries in Tibet, Gadan Monastery was founded by Tsong Khapa himself in 1409.

In 1414, 5 years after the founding of Gadan, one of the closest disciples of Je Tsong Khapa, Tsako Ngawang Drakpa, established Dhe-Tsang Monastery, the 2nd Gelugpa monastery, in eastern Tibet.

Jamyang Choje Tashi Pelden founded Drepung Monastery in 1416. At one time it had 7 colleges but these were later amalgated into 4, Loseling, Gomang, Deyang and Ngagpa. Of the 4 colleges, only the Loseling and Gomang have survived up to the present time.

Another of Tsong Khapa's spiritual sons, Jamchen Choje Sakya Yeshe established Sera Monastery in 1419. The Monastery initially had 5 colleges which were later amalgated into 3, Sera-Mey, Sera-Ngagpa and Sera-Je. Similarly, Gyalwa Gendun Drup, the First Dalai Lama, founded Tashi Lhunpo Monastery at Shigatse in 1447, which was to become the seat of the successive Panchen Lamas.

The Lower Tantric College, Gyume, was established by Je Sherab Sengey in 1440, and the Upper Tantric College Gyuto by Gyuchen Kunga Dhondup in 1474. At their peak there were more than 5,000 monks in each of the monastic universities around Lhasa - Gadan, Drepung and Sera - while there were at least 500 in each tantric college. Young men would travel from all three regions of Tibet to enroll at these monastic universities as monks in order to receive an education and spiritual training. The Gelugpa tradition lays special emphasis on the place of ethics, as expressed through monastic discipline, as the ideal basis for religious education and practice. Consequently, the great majority of Gelugpa lamas are monks. In addition, the Gelugpa tradition regards sound scholarship as a prerequisite for constructive meditation, hence, the teachings of both sutra and tantra are subject to rigorous analysis through the medium of dialectical debate.

In general, the curriculum of study covers the five major topics-the perfection of wisdom, philosophy of the Middle Way, valid cognition, phenomenology and monastic discipline. These 5 are studied meticulously by the dialectical method using Indian texts as well as Indian and Tibetan commentaries to them, often textbooks unique to each monastic tradition, for a period of 15 to 20 years.