Gmina Żarnów is a rural gmina (administrative district) in Opoczno County, Łódź Voivodeship, in central Poland. Its seat is the village of Żarnów, which lies approximately 18 kilometres (11 mi) south-west of Opoczno and 77 km (48 mi) south-east of the regional capital Łódź.

The gmina covers an area of 140.7 square kilometres (54.3 sq mi), and as of 2006 its total population is 6,260.

Gmina Żarnów contains the villages and settlements of Adamów, Afryka, Antoniów, Bronów, Budków, Chełsty, Dąbie, Dłużniewice, Grębenice, Jasion, Kamieniec, Klew, Klew-Kolonia, Ławki, Łysa Góra, Malenie, Malków, Marcinków, Miedzna Murowana, Młynek, Myślibórz, Nadole, Niemojowice, Niemojowice-Kolonia, Nowa Góra, Odrowąż, Paszkowice, Pilichowice, Poręba, Ruszenice, Ruszenice-Kolonia, Siedlów, Sielec, Skórkowice, Skumros, Soczówki, Straszowa Wola, Tomaszów, Topolice, Trojanowice, Widuch, Wierzchowisko, Żarnów and Zdyszewice.

Gmina Żarnów is bordered by the gminas of Aleksandrów, Białaczów, Fałków, Końskie, Paradyż and Ruda Maleniecka.

• Polish official population figures 2006