Loimaa is a town and 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 7,185 (2003) and covers an area of 47.78 km² of which 0.30 km² is water. The population density is 150.4 inhabitants per km². The municipality is unilingually Finnish.

The town of Loimaa merged with Loimaan kunta (literally "municipality of Loimaa") on January 1, 2005.