Teuva (Swedish:Östermark) is a municipality of Finland.

It is located in the province of Western Finland and is part of the Southern Ostrobothnia region. The population of Teuva is 5,535 (30 June 2015) and the municipality covers an area of 554.66 km (214.16 sq mi) of which 1.35 km (0.52 sq mi) is inland water (1 January 2011). The population density is 9.98/km (25.8/sq mi).