As countries like Finland and Sweden shift away from neutrality to join NATO, the war has prompted a reevaluation of neutrality's relevance within European security. Mostly known as a political concept, this article explores the legal principle of neutrality in the context of the Ukrainian-Russian war, where military aid from numerous states has sparked debate on the boundaries of neutrality in modern conflicts. The narrow legal framework of neutrality highlights the ambivalence of the legal obligations of neutral states where abstention from supporting belligerents and help to a state defending against aggression coexist. Therefore, the rigidity of traditional neutrality law appears to be challenged by the ongoing war shifting towards more flexible interpretations in the face of collective security threats. Consequently, the need to adpat the legal doctrine in the rapidly changing landscape of international law and warfare underlines the obsolescence of the concept.