Although espionage is widely practiced, it remains legally ambiguous under international law. This study comparatively examines the legal status of espionage in times of war and peace; it outlines how the law of armed conflict defines and limits espionage through its foundational legal sources and then discusses the normative gaps arising from the absence of a clear international framework regulating espionage activities in peacetime. In this context, the study identifies the distinctions between espionage and general intelligence activities, analyzes wartime legal instruments (such as the Lieber Code and the Hague and Geneva Conventions), evaluates various views on the legality of espionage in peacetime, and assesses its practical dimensions through case studies such as the U-2 Crisis, the Eli Cohen incident, and the Stuxnet attack. The lack of a binding international regulation on peacetime espionage has perpetuated its status as a legally grey area, reflecting a delicate tension between state security interests and the fundamental principles of international law
