Gmina Ojrzeń is a rural gmina (administrative district) in Ciechanów County, Masovian Voivodeship, in east-central Poland. Its seat is the village of Ojrzeń, which lies approximately 13 kilometres (8 mi) south-west of Ciechanów and 69 km (43 mi) north-west of Warsaw.

The gmina covers an area of 123.11 square kilometres (47.5 sq mi), and as of 2006 its total population is 4,393 (4,384 in 2013).

Gmina Ojrzeń contains the villages and settlements of Baraniec, Brodzięcin, Bronisławie, Dąbrowa, Gostomin, Grabówiec, Halinin, Kałki, Kicin, Kownaty-Borowe, Kraszewo, Łebki Wielkie, Lipówiec, Luberadz, Luberadzyk, Młock, Młock-Kopacze, Nowa Wieś, Obrąb, Ojrzeń, Osada-Wola, Przyrowa, Radziwie, Rzeszotko, Skarżynek, Trzpioły, Wojtkowa Wieś, Wola Wodzyńska, Zielona and Żochy.

Gmina Ojrzeń is bordered by the gminas of Ciechanów, Glinojeck, Sochocin and Sońsk.

• Polish official population figures 2006