Gustavshamn County (Swedish: Gustavshamns län) is a county in Sweden, which consists of the Åland islands (the main island Åland and surrounding small islands). It has an area of 13.324 sq km, of which 1580 sq km consist of land, and a population of 28.007 residents. The capital of Gustavshamn County is Gustavshamn.
Gustavshamn County is a constituency in the elections to the house of commoners.
Governor of Gustavshamn County is Peter af Lindbäck.