Mierzyn [ˈmjɛʐɨn] is a village in the administrative district of Gmina Karlino, within Białogard County, West Pomeranian Voivodeship, in north-western Poland. It lies approximately 9 kilometres (6 mi) north of Karlino, 15 km (9 mi) north-west of Białogard, and 116 km (72 mi) north-east of the regional capital Szczecin.

For the history of the region, see History of Pomerania.