Jiashan County (simplified Chinese: 嘉善县; traditional Chinese: 嘉善縣; pinyin: Jiāshàn Xiàn) is a county in the north of Zhejiang Province, bordering Shanghai to the northeast and Jiangsu province to the north.

The county seat is located on 126 People Avenue, Weitang Town.

The second campus of Sanda University, known as Guangbiao Institute, is located in Jiashan County.

On 1 November 2022, the county was named by a guideline of the National Development and Reform Commission (NDRC) as a "leading trial area" for common prosperity.

[1] Jiashan County consists of six towns, three subdistricts, 11 communities, 16 residential zones and 164 administrative villages.