Zastawie [zasˈtavjɛ] is a village in the administrative district of Gmina Wąsewo, within Ostrów Mazowiecka County, Masovian Voivodeship, in east-central Poland. It lies approximately 2 kilometres (1 mi) south of Wąsewo, 18 km (11 mi) north-west of Ostrów Mazowiecka, and 86 km (53 mi) north-east of Warsaw.