Yanyuan County (Chinese: 盐源县; pinyin: Yányuán Xiàn; Yi: ꑸꑼꑤ yiep yuop xiep, also ꋂꂿꑤ ce mo xiep) is a county in Liangshan Prefecture, Sichuan Province, China, bordering Yunnan province to the west.

Yanyuan County was originally inhabited by the Yi people, but has since been incorporated into Han Chinese culture.

In the 2010s, a new tunnel was built through the mountains east of Yanyuan to connect the county with the prefecture capital of Xichang.

In the west, Yanyuan County encompasses the eastern shores of Lugu Lake, shared with Yunnan Province.

To the north and east, Yanyuan is bordered by the Yalong River that cuts a deep gorge through the mountains.