This entry provides a comprehensive review of one of the most dynamic and prolific areas of law to develop over the past 30 years. International criminal law provides guidance through norms and principles for the international community to legally prosecute individuals, even if national governments attempt to avoid prosecuting their own nationals for international crimes. It is a principle of law that repudiates impunity and embraces accountability. The essay covers international and domestic war crimes tribunals, the ICJ, universal jurisdiction, treaties (e.g., Geneva Conventions, the Convention on the Prevention and Punishment of the Crime of Genocide, and the Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment), international customary law, immunity, and command responsibility, amongst other salient international criminal law principles.