Mężyk [ˈmɛ̃ʐɨk] is a village in the administrative district of Gmina Wieleń, within Czarnków-Trzcianka County, Greater Poland Voivodeship, in west-central Poland. It lies approximately 10 kilometres (6 mi) south-east of Wieleń, 22 km (14 mi) west of Czarnków, and 66 km (41 mi) north-west of the regional capital Poznań.