Rząśnik (Polish pronunciation: [ˈʐɔ̃ɕɲik]) is a village in Wyszków County, Masovian Voivodeship, in east-central Poland. It is the seat of the gmina (administrative district) called Gmina Rząśnik. It lies approximately 14 kilometres (9 mi) north-west of Wyszków and 60 km (37 mi) north-east of Warsaw.