The name Tây Sơn is used in Vietnamese history in various ways to refer to the period of peasant rebellions and decentralized dynasties established between the end of the figurehead Lê dynasty in 1770 and the beginning of the Nguyễn dynasty in 1802.

The name of the rebel leaders' home district, Tây Sơn, comes to be applied to the leaders themselves (the Tây Sơn brothers: i.e., Nguyễn Nhạc, Huệ, and Lữ), their uprising (the Tây Sơn Uprising) or their rule (the [Nguyễn] Tây Sơn dynasty).