Gmina Wieliszew is a rural gmina (administrative district) in Legionowo County, Masovian Voivodeship, in east-central Poland. Its seat is the village of Wieliszew, which lies approximately 7 kilometres (4 mi) north-east of Legionowo and 26 km (16 mi) north of Warsaw.
The gmina covers an area of 102.23 square kilometres (39.5 sq mi), and as of 2006 its total population is 8,483.
Gmina Wieliszew contains the villages and settlements of Góra, Janówek Pierwszy, Kałuszyn, Komornica, Krubin, Łajski, Michałów-Reginów, Olszewnica Nowa, Olszewnica Stara, Poddębie, Sikory, Skrzeszew, Topolina and Wieliszew.
Gmina Wieliszew is bordered by the towns of Legionowo and Nowy Dwór Mazowiecki, and by the gminas of Jabłonna, Nieporęt, Pomiechówek and Serock.