Wąsosz [ˈvɔ̃sɔʂ] is a village in Grajewo County, Podlaskie Voivodeship, in north-eastern Poland. It is the seat of the gmina (administrative district) called Gmina Wąsosz. It lies approximately 17 kilometres (11 mi) south-west of Grajewo and 73 km (45 mi) north-west of the regional capital Białystok.