Rząśnik Włościański (Polish pronunciation: [ˈʐɔ̃ɕɲik fwɔɕˈtɕaj̃skʲi]) is a village in the administrative district of Gmina Wąsewo, within Ostrów Mazowiecka County, Masovian Voivodeship, in east-central Poland. It lies approximately 14 kilometres (9 mi) north-west of Ostrów Mazowiecka and 87 km (54 mi) north-east of Warsaw.