Zakrzewek [zaˈkʂɛvɛk] (German: Seemark; before 1907: Zakrzewke) is a village in the administrative district of Gmina Więcbork, within Sępólno County, Kuyavian-Pomeranian Voivodeship, in north-central Poland. It lies approximately 5 kilometres (3 mi) north-west of Więcbork, 10 km (6 mi) south-west of Sępólno Krajeńskie, and 48 km (30 mi) north-west of Bydgoszcz.