The right of States to punish persons who have committed war crimes in non international armed conflicts exists in international law. This applies regardless
of the nationality of the accused person and irrespective of the place of commission of the crime. The right is not codified in international law, unlike the same right in respect of war crimes committed in international armed conflicts. This article analyses the legislation enacted in Ireland to hold individuals accountable for extraterritorial violations of international humanitarian law. It concludes that Irish legislation is largely in line with international law, except in respect of the exercise of universal jurisdiction over war crimes committed during non-international armed conflicts. Thus, customary international law would have to be relied on to try such crimes in Ireland. The article asserts that the restrictive approach adopted by the courts in interpreting the application of customary international law in Ireland would impede the exercise of universal jurisdiction over war crimes committed in non-international armed conflicts.