Nam Som (Thai: น้ำโสม, pronounced [náːm sǒːm]) is a district (amphoe) in the northwestern part of Udon Thani province, northeastern Thailand.

Na Yung-Nam Som National Park lies within the district's boundaries.

[3] The district is divided into seven sub-districts (tambons), which are further subdivided into 80 villages (mubans).

Na Ngua covers parts of tambons Na Ngua and Si Samran; Nam Som cover parts of tambons Nam Som and Si Samran.

Missing numbers are tambon which now form Na Yung District.