Gmina Grodzisk Mazowiecki is an urban-rural gmina in Grodzisk Mazowiecki County, Masovian Voivodeship, in east-central Poland. Its seat is the town of Grodzisk Mazowiecki, which lies approximately 29 kilometres south-west of Warsaw. The gmina covers an area of 107.03 square kilometres, and as of 2006 its total population is 37,432.