Osiek [ˈɔɕɛk] is a village in Brodnica County, Kuyavian-Pomeranian Voivodeship, in north-central Poland. It is the seat of the gmina (administrative district) called Gmina Osiek. It lies approximately 10 kilometres (6 mi) south of Brodnica and 54 km (34 mi) east of Toruń.