The NATO Joint Civil/Military Frequency Agreement (NJFA) is a document negotiated between the civil and military frequency management authorities of NATO member states that regulates the use of radio spectrum for military purposes in accordance with NATO requirements and is approved by the North Atlantic Council.

In addition to regulating the allied-military frequency use, the NJFA plays an important role in the adoption of a coherent allied spectrum policy, in the processes of Euro-Atlantic frequency harmonization and in the development of alliance-related systems and equipment.

The NJFA defines NATO harmonized frequency bands for common military frequency use in European member states of NATO.

Harmonization aims at more efficient frequency use, while at the same time providing better frequency access to military users, thereby supporting NATO activities.