Gmina Somianka is a rural gmina (administrative district) in Wyszków County, Masovian Voivodeship, in east-central Poland. Its seat is the village of Somianka, which lies approximately 12 kilometres (7 mi) west of Wyszków and 44 km (27 mi) north-east of Warsaw.

The gmina covers an area of 116.38 square kilometres (44.9 sq mi), and as of 2006 its total population is 5,491 (5,591 in 2013).

Gmina Somianka contains the villages and settlements of:

• Barcice
• Celinowo
• Henrysin
• Huta Podgórna
• Jackowo Dolne
• Jackowo Górne
• Janki
• Jasieniec
• Kręgi
• Michalin
• Nowe Kozłowo
• Nowe Płudy
• Nowe Wypychy
• Ostrowy
• Popowo-Letnisko
• Popowo-Parcele
• Skorki
• Somianka (including the sołectwos of Somianka Zaszosie and Somianka-Parcele)
• Stare Kozłowo
• Stare Płudy
• Stare Wypychy
• Stary Mystkówiec
• Suwin
• Ulasek
• Wielątki Rosochate
• Wielęcin
• Wola Mystkowska
• Wólka Somiankowska
• Zdziebórz

Gmina Somianka is bordered by the gminas of Dąbrówka, Rząśnik, Serock, Wyszków and Zatory.

• Polish official population figures 2006