Lasek [ˈlasɛk] is a village in the administrative district of Gmina Celestynów, within Otwock County, Masovian Voivodeship, in east-central Poland. It lies approximately 3 kilometres (2 mi) west of Celestynów, 10 km (6 mi) south-east of Otwock, and 31 km (19 mi) south-east of Warsaw.