Zhangwu County (Chinese: 彰武; pinyin: Zhāngwǔ) is a county in the north of Liaoning province, China.

It is under the administration of Fuxin City, the centre of which lies 82 kilometres (51 mi) to the southwest, with a population of 333,643 in 2020 residing in an area of 3,635 km2 (1,403 sq mi).

Zhangwu County has a monsoon-influenced humid continental climate (Köppen Dwa), with great seasonal contrast in temperature, precipitation, and humidity.

Precipitation is very low in winter and is heavily concentrated in the summer months.

With monthly percent possible sunshine ranging from 46% in July to 67% in January and February, there are 2,673 hours of bright sunshine annually.