Xiasi is a town located in the Kaili City region of the Guizhou province in China. It covers a total area of 154 square kilometers and was officially established in 1931.
The town has a population of approximately 35,000 residents. The local demographic is characterized by the presence of native ethnic minorities, specifically the Miao and Mulao people. On September 25, 2014, Xiasi was transitioned from a former administrative division of Majiang to become part of Kaili.