Si Sawat (Thai: ศรีสวัสดิ์, pronounced [sǐː sā.wàt]) is a district (amphoe) in Kanchanaburi province, western Thailand.

The district is dominated by the Si Nakharin Reservoir, which is part of Khuean Srinagarindra National Park.

The 140-metre-high Si Nakharin Dam was finished in 1980 and creates a 419 km2 impoundment of the Kwae Yai River.

The dam has received criticism for being built on the Si Sawat fault line.

The district is divided into six sub-districts (tambons), which are further subdivided into 33 villages (mubans).