Twenty years have passed since the International Court of Justice has issued its controversial advisory opinion on the threat or use of nuclear weapons and it is questionable whether the courts rather ambiguous reasoning would still be applicable today. With the rapid development of new norms and twenty years of new case law it might proof difficult to uphold the courts conclusions. With regard to disarmament, Art VI of the Nuclear Non-Proliferation Treaty (NPT) is still the only legally binding, universal nuclear disarmament clause and its exact content remains subject to various disputes. Under these circumstances, many states and civil society initiatives question the effectiveness of Art VI and the NPT as such and call for negotiations of a comprehensive nuclear weapon convention to begin. After a short historical overview on nuclear diplomacy and the respective developments in international law, this thesis tries to analyze the current situation of the legality of nuclear weapons. It will critically reflect on the ICJs advisory opinion while trying to identify remaining legal gaps for a lawful use. Since the question of the legality of nuclear weapons is inherently linked with nuclear disarmament, the subsequent chapter will focus on the obligations set forth in Art VI of the NPT, which constitutes the cornerstone of the modern nuclear disarmament regime. It will try to assess whether Art VI contains substantive disarmament obligations and whether this legal framework is sufficient for the achievement of comprehensive nuclear disarmament in the future. Again, the thesis tries to critically reflect on the ICJs interpretation of Art VI. The final chapter will then try to identify ways to address the remaining legal gaps and tries to establish how a comprehensive legal framework for the prohibition and complete disarmament of nuclear weapons could be developed.