Kadłubek [kaˈdwubɛk] is a village in the administrative district of Gmina Sienno, within Lipsko County, Masovian Voivodeship, in east-central Poland. It lies approximately 5 kilometres (3 mi) north-east of Sienno, 10 km (6 mi) south-west of Lipsko, and 128 km (80 mi) south of Warsaw.