Bartosy [barˈtɔsɨ] is a village in the administrative district of Gmina Wąsewo, within Ostrów Mazowiecka County, Masovian Voivodeship, in east-central Poland. It lies approximately 19 kilometres (12 mi) north-west of Ostrów Mazowiecka and 89 km (55 mi) north-east of Warsaw.