Shangsi County
| Shangsi County 上思县 · Sangswh Yen Shangsze | |
|---|---|
| Coordinates: 22°09′13″N 107°58′55″E / 22.1536°N 107.982°E | |
| Country | China | 
| Autonomous region | Guangxi | 
| Prefecture-level city | Fangchenggang | 
| County seat | Siyang | 
| Area | |
|  • Total | 2,816 km2 (1,087 sq mi) | 
| Population  (2020) | |
|  • Total | 194,774 | 
| • Density | 69/km2 (180/sq mi) | 
| Time zone | UTC+8 (China Standard) | 
Shangsi County (Chinese: 上思县; pinyin: Shàngsī Xiàn; Zhuang: Sangswh Yen) is a county in the southwest of Guangxi, China. It is the northernmost county-level division of Fangchenggang City.