Situated in Dranang, Samye Monastery was completed in 779 under the patron of Trisong Detsen. At the time of Samye's construction, Buddhism had been transmitted into Tibet, but there were no formal Buddhist priests or rituals. Trisong Detsen decided to invite Santarakshita and Padmasambhava, both Buddhist figureheads in India, to promote Buddhism in Tibet and participate in the construction of a monastery. Padmasambhava chose the construction site while the design was done by Santarakshita. After the construction was completed, Buddhism became the official religion in Tibet. Learned monks from inland China and India were invited to Tibet to translate Buddhist sutras into Tibetan. Trisong Detsen selected seven nobles to be the first monks in Tibet. Samye became the first formal monastery that established "triratna", referring to the Buddha, the Dharma and the Sangha, or Buddhist priesthood.

Samye means "unimaginable" in Tibetan. It was said that when Tritsong Detsen asked for suggestions about the construction of the monastery, Padmasambhava, exerting his magic power, showed the king an image of a monastery in his palm. That is the origin of the name.

The monastery combines the styles of China, Tibet and India, and the layout was designed to represent the ideal universe described in Buddhist scriptures. "Utse", the Great Hall symbolizing "Sumeru" in perfect Buddhist universe, is the largest structure in the monastery. The Sun and Moon chapels encircle the large hall, and four "stupas" of different styles stand at each corner of the room. These "stupas" are colored in red, white, black and green to represent the four Heavenly Kings. Four larger halls and eight smaller ones, evenly distributed around "Utse," represent the oceans in that universe. The monastery is secluded from the outside world by a circular wall with thousands of Buddha statues sitting on it. This wall represents a mountain near the border of the universe.