Trisong Detsän or Trisong Detsen is the son of Me Agtsom and one of the emperors of Tibet and rules from 755 until 797 or 804 CE.

Trisong Detsen is the second of the Three Dharma Kings of Tibet, playing a pivotal role in the introduction of Buddhism to Tibet and the establishment of the Nyingma, or 'Ancient' school of Tibetan Buddhism.

Trisong has five wives, all of whom come from Tibetan noble families.

According to the later hagiographic tradition of Padmasambhava, Yeshe Tsogyal, the Princess of Karchen is a wife of the emperor and also one of Padmasambhava's consorts.

She is said to have recorded Padmasambhava's teachings and become known for her own Buddhist realizations.

Another wife, Tse Pongza, the principal wife of Trisong Detsen, and the mother of the heir apparent, becomes known for being the counterpole of Padmasambhava and Yeshe Tsogyal, fighting for the Bön religion and against Buddhism.

One of Trisong Detsen's children is Princess Pema Sal, who was entrusted by Padmasambhava with an important terma.

The empire Trisong Detsen inherited had declined somewhat from its greatest extent under the first Dharma King, Songtsen Gampo.

Disintegration continues during Trisong Detsen's reign when, in 694, Tibet loses control of several cities in Turkestan and, in 703, Nepal breaks into rebellion.

Meanwhile, Arab forces vie for influence along the western border lands of the Tibetan empire.