The Xiao River (Chinese: 瀟水; pinyin: Xiāoshuǐ [ɕjáʊ.ʂwèɪ]) is the Main Stream of the upper Xiang River located in Yongzhou, Hunan.

As of 2011 Water Census of China, it has a length of 365 kilometres (227 mi) from the headwaters to the confluence in the Ping Island of Yongzhou with the Xiang River West Branch (Left Branch) originating from Guangxi.

With the tributaries, its drainage basin area is 12,094 square kilometres (4,670 sq mi).

The tributaries of the Xiao reach Lianzhou of Guangdong and Guangxi.

Originating from the southern side of Yegou Mountain (野狗岭) in Zhulin Village (竹林村) of Xiangjiangyuan Township, Lanshan County, the Xiao River flows southwest to northeast through Lanshan, Jianghua, Jiangyong, Ningyuan, Dao, Shuangpai and Lingling seven counties, joining the Main Stem of the Xiang at the confluence in Ping Island of Yongzhou with the West Branch from Guangxi.