Gmina Zarszyn is a rural gmina (administrative district) in Sanok County, Subcarpathian Voivodeship, in south-eastern Poland. Its seat is the village of Zarszyn, which lies approximately 15 kilometres (9 mi) west of Sanok and 50 km (31 mi) south of the regional capital Rzeszów.
The gmina covers an area of 105.96 square kilometres (40.9 sq mi), and as of 2006 its total population is 9,225.
Gmina Zarszyn contains the villages and settlements of Bażanówka, Chmurówka, Długie, Granicznik, Jaćmierz, Koszary, Mroczkówki, Nowosielce, Odrzechowa, Pastwiska, Pielnia, Posada Jaćmierska Górna, Posada Zarszyńska and Zarszyn.
Gmina Zarszyn is bordered by the gminas of Besko, Brzozów, Bukowsko, Haczów, Rymanów and Sanok.