Gmina Czosnów is a rural gmina (administrative district) in Nowy Dwór Mazowiecki County, Masovian Voivodeship, in east-central Poland. Its seat is the village of Czosnów, which lies approximately 7 kilometres (4 mi) south-east of Nowy Dwór Mazowiecki and 26 km (16 mi) north-west of Warsaw.
The gmina covers an area of 128.34 square kilometres (49.6 sq mi), and as of 2006 its total population is 8,743 (9,474 in 2011).
Gmina Czosnów contains the villages and settlements of Adamówek, Aleksandrów, Augustówek, Brzozówka, Cybulice, Cybulice Duże, Cybulice Małe, Cząstków Mazowiecki, Cząstków Polski, Czeczotki, Czosnów, Dąbrówka, Dębina, Dobrzyń, Izabelin-Dziekanówek, Janów-Mikołajówka, Janówek, Jesionka, Kaliszki, Kazuń Nowy, Kazuń Polski, Kazuń-Bielany, Kiścinne, Łomna, Łomna Las, Łosia Wólka, Małocice, Palmiry, Pieńków, Sady, Sowia Wola, Sowia Wola Folwarczna, Truskawka, Wiersze, Wólka Czosnowska and Wrzosówka.
Gmina Czosnów is bordered by the town of Nowy Dwór Mazowiecki and by the gminas of Izabelin, Jabłonna, Leoncin, Leszno, Łomianki and Zakroczym.