Gmina Korsze is an urban-rural gmina (administrative district) in Kętrzyn County, Warmian-Masurian Voivodeship, in northern Poland. Its seat is the town of Korsze, which lies approximately 19 kilometres (12 mi) north-west of Kętrzyn and 61 km (38 mi) north-east of the regional capital Olsztyn.
The gmina covers an area of 249.94 square kilometres (96.5 sq mi), and as of 2006 its total population is 10,561 (out of which the population of Korsze amounts to 4,632, and the population of the rural part of the gmina is 5,929).