Janowiec Kościelny [jaˈnɔvjɛt͡s kɔɕˈt͡ɕɛlnɨ] is a village in Nidzica County, Warmian-Masurian Voivodeship, in northern Poland. It is the seat of the gmina (administrative district) called Gmina Janowiec Kościelny. It lies approximately 10 kilometres (6 mi) south-east of Nidzica and 55 km (34 mi) south of the regional capital Olsztyn.