Jalasjärvi is a former municipality of Finland. It was merged to the town of Kurikka on 1 January 2016.
It is located in the province of Western Finland and is part of the Southern Ostrobothnia region. The population of Jalasjärvi was 7,834 (30 June 2015) and covered a land area of 818.70km (316.10sqmi). The population density was 9.5688/km (24.7832/sqmi).