Ostrówek [ɔsˈtruvɛk] is a village in the administrative district of Gmina Klembów, within Wołomin County, Masovian Voivodeship, in east-central Poland. It lies approximately 4 kilometres (2 mi) south-east of Klembów, 10 km (6 mi) east of Wołomin, and 32 km (20 mi) north-east of Warsaw.