Halsua (Swedish: Halso) is a municipality of Finland.
Halsua is located in the province of Western Finland and is part of the Central Ostrobothnia region. The municipality has a population of about 1200 in 2019's and covers an area of 428.34 square kilometres (165.38 sq mi) of which 15.63 km2 (6.03 sq mi) is water. The population density is 2.42 inhabitants per square kilometre (6.3/sq mi).
Neighbouring municipalities are Kaustinen, Kokkola, Lestijärvi, Perho and Veteli.
The municipality is unilingually Finnish.