Weishan Yi and Hui Autonomous County (; Xiao'erjing: ; Bai: ) is an autonomous county in the Dali Bai Autonomous Prefecture, in northwestern Yunnan Province, China. It was known as Menghua () until the 1950s.
Weishan borders Midu County to the east, Nanjian County and Fengqing County to the south, Yangbi County and Changning County to the west, and Dali City to the north.
It is situated in the upper section of the Ailao Mountains and the Wuliang Mountains.
Weishan Yi and Hui Autonomous County has 4 towns and 6 townships.
Weishan has a rail station called Weishan Railway Station, with services to Dali City and Lincang.