Osiek-Aleksandrowo [ˈɔɕɛk alɛksanˈdrɔvɔ] is a village in the administrative district of Gmina Gołymin-Ośrodek, within Ciechanów County, Masovian Voivodeship, in east-central Poland. It lies approximately 5 kilometres (3 mi) south-east of Gołymin-Ośrodek, 22 km (14 mi) south-east of Ciechanów, and 64 km (40 mi) north of Warsaw.