The thesis explores the possibility to apply the law of occupation by analogy to territories controlled by non-State armed groups. It argues that the law regulating NIAC has a gap with respect to these territories. It further argues that the law of occupation is suitable as this law reflects the unique context that arises from situations of occupation and control of territories by foreign forces. The thesis underlines that regulating the behaviour of armed groups by international human rights law is not as adequate as the law of occupation. For this purpose the thesis reviews the definition of armed groups in international humanitarian law and the prerequisites of the law of occupation. It then addresses the principle of effectiveness and its place in determining the status of armed groups in international law. Lastly, the thesis turn to explore how would the law apply to territories controlled by armed groups.