Gmina Zalewo is an urban-rural gmina (administrative district) in Iława County, Warmian-Masurian Voivodeship, in northern Poland. Its seat is the town of Zalewo, which lies approximately 28 kilometres (17 mi) north of Iława and 59 km (37 mi) west of the regional capital Olsztyn.
The gmina covers an area of 254.34 square kilometres (98.2 sq mi), and as of 2006 its total population is 6,986 (out of which the population of Zalewo amounts to 2,152, and the population of the rural part of the gmina is 4,834).