Pustelnik [pusˈtɛlɲik] is a village in the administrative district of Gmina Brzeźnio, within Sieradz County, Łódź Voivodeship, in central Poland. It lies approximately 3 kilometres (2 mi) north of Brzeźnio, 14 km (9 mi) south-west of Sieradz, and 66 km (41 mi) south-west of the regional capital Łódź.