Kostów [ˈkɔstuf] is a village in the administrative district of Gmina Byczyna, within Kluczbork County, Opole Voivodeship, in south-western Poland. It lies approximately 8 kilometres (5 mi) north-west of Byczyna, 21 km (13 mi) north of Kluczbork, and 58 km (36 mi) north of the regional capital Opole.