The NATO M band is the obsolete designation given to the radio frequencies from 60 to 100 GHz (equivalent to wavelengths between 5 and 3 mm) during the cold war period. Since 1992 frequency allocations, allotment and assignments are in line to NATO Joint Civil/Military Frequency Agreement (NJFA).

However, in order to identify military radio spectrum requirements, e.g. for crises management planning, training, Electronic warfare activities, or in military operations, this system is still in use.

The NATO M band is also a subset of the EHF band as defined by the ITU. It intersects with the V (50–75 GHz) and W band (75–110 GHz) of the older IEEE classification system.