Janówek [jaˈnuvɛk] is a village in the administrative district of Gmina Czosnów, within Nowy Dwór County, Masovian Voivodeship, in east-central Poland. It lies approximately 5 kilometres (3 mi) south of Czosnów, 10 km (6 mi) south of Nowy Dwór Mazowiecki, and 24 km (15 mi) north-west of Warsaw.