Gmina Konstancin-Jeziorna is an urban-rural gmina in Piaseczno County, Masovian Voivodeship, in east-central Poland. Its seat is the town of Konstancin-Jeziorna, which lies approximately 8 kilometres east of Piaseczno and 17 km south-east of Warsaw. The gmina covers an area of 78.28 square kilometres, and as of 2006 its total population is 23,229. The gmina contains part of the protected area called Chojnów Landscape Park.