The Tây Sơn dynasty (Vietnamese: [təj ʂəːn], Vietnamese: Nhà Tây Sơn, Chữ Nôm: 茹西山, lit. 'House of Tây Sơn'; Vietnamese: triều Tây Sơn, officially Great Việt, was a dynasty of Vietnam. It was founded after three Nguyễn brothers from the village of Tây Sơn rebelled against the Lê dynasty, Nguyễn lords, and Trịnh lords. The Tây Sơn were led by these three brothers, referred to by modern Vietnamese historians as the Tây Sơn brothers because of their origin in the district of Tây Sơn. The Tây Sơn was later succeeded by the Nguyễn dynasty.

Emperor Quang Trung or Nguyễn Huệ, also known as Nguyễn Quang Bình, was the second emperor of the Tây Sơn dynasty, reigning from 1788 until 1792. He was also one of the most successful military commanders in Vietnam's history. Nguyễn Huệ and his brothers, Nguyễn Nhạc and Nguyễn Lữ, together known as the Tây Sơn brothers, were the leaders of the Tây Sơn rebellion. As rebels, they conquered Vietnam, overthrowing the imperial Later Lê dynasty and the two rival feudal houses of the Nguyễn in the south and the Trịnh in the north.