Determining the responsibility of a state for complicity in the internationally wrongful act of a non-state armed group is an issue that requires analysis from a general international law standpoint. There are numerous ongoing conflicts throughout the world, which are fought by states and non-state armed groups. In the course of such violence, rules of international humanitarian law and international human rights law are breached. There is abundant practice of states rendering aid or assistance to non-state armed groups in their undertakings, whether through the provision of weapons, financial aid, logistical support, intelligence sharing, and/or otherwise. Therefore, when non-state armed groups commit internationally wrongful acts that have been helped by states through such avenues, complicity becomes a pertinent issue. This article addresses and answers the following question: how can the responsibility of a state be established for complicity in the unlawful act(s) of a non-state armed group?