Champasak is a province in southwestern Laos, near the borders with Thailand and Cambodia. It is one of the three principalities that succeeded the Lao kingdom of Lan Xang. As of the 2015 census, it had a population of 694,023. The capital is Pakse, but it takes its name from Champasak, the former capital of the Kingdom of Champasak.
Champasak has played a central role in the history of Siam and Laos, with frequent battles taking place in and around Champasak. Its rich cultural heritage includes ancient temple ruins and French colonial architecture.