Västanfjärd is a former municipality of Finland. On January 1, 2009, it was consolidated with Dragsfjärd and Kimito to form the new municipality of Kimitoön.
It is located in the province of Western Finland and is part of the Southwest Finland region. The municipality had a population of 812 (2004-12-31) and covered an area of 96.62 km² (excluding sea) of which 0.69 km² is inland water. The population density was 8.46 inhabitants per km².
The municipality was bilingual, with majority being Swedish and minority Finnish speakers.
Coordinates: 60°03′00″N 22°40′00″E / 60.05000°N 22.66667°E