Masku is a municipality of Finland. It is located in the province of Western Finland and is part of the Southwest Finland region. The municipality, which is located about 17 kilometres just north of Turku, has a population of 9,619 and covers an area of 204.01 square kilometres of which 29.21 km2 is water. The population density is 55 inhabitants per square kilometre. The municipality is unilingually Finnish. The municipality has also been known as "Masko" in Swedish.