The Norwegian Institute for Defence Studies (Norwegian: Institutt for forsvarsstudier, IFS) is a defence research institute based in Oslo, Norway. It was established in 1980.
It is a politically independent institute, subordinate to the Norwegian Defence Education Centre within the Norwegian Armed Forces. Its purpose is to "conduct research into the problem areas Norwegian security policies and Defence in a sociological perspective".
It is divided into three Departments; Norwegian security policy, Civil-military relations and International security policy, as well as the Centre for Transatlantic Studies. The current director general of IFS is historian Rolf Tamnes.