Niemierzyn [ɲɛˈmjɛʐɨn] is a village in the administrative district of Gmina Ostrówek, within Wieluń County, Łódź Voivodeship, in central Poland. It lies approximately 4 kilometres (2 mi) south of Ostrówek, 10 km (6 mi) north of Wieluń, and 80 km (50 mi) south-west of the regional capital Łódź.

The locale's designation derives from the Slavic given name Niemir.