Sauvo (Sagu in Swedish) is a municipality of Finland.

It is located in the province of Western Finland and is part of the Finland Proper region. The municipality has a population of 2,910 (2004) and covers an area of 252.65 km² of which 1.13 km² is water. The population density is 11.5 inhabitants per km². Like many areas near water, the population of Sauvo increases every summer because of summer cottage usage. While not counted officially to statistics the increase will roughly double the population during summer.

The municipality is unilingually Finnish.