Sasek Wielki (Polish pronunciation: [ˈsasɛk ˈfjɛlkʲi]; German: Materschobensee) is a village in the administrative district of Gmina Szczytno, within Szczytno County, Warmian-Masurian Voivodeship, in northern Poland. It lies approximately 7 kilometres (4 mi) south-west of Szczytno and 41 km (25 mi) south-east of the regional capital Olsztyn.