This article examines the applicability of international law in the context of targeted killing conducted by states. Targeted killing has become part of the conventional military and security strategy of a number of states in their operations against terrorist suspects. In particular, Israel, the US and Russia are some of the most notable states that have openly employed such tactics. Controversy has arisen regarding whether such acts should be considered as part of an ongoing ‘war’ against terrorist organizations, thus judged according to the law on the use of force (jus ad bellum) and the law of armed conflict (jus in bello or international humanitarian law (IHL)), or whether the fight against terrorist groups should be considered within a domestic law enforcement framework, thus engaging international human rights law (IHRL). This article is also relevant to the situation in Southeast Turkey, as it identifies the gaps existing in international law in relation to the question of when the act of killing can trigger the applicability of IHL and IHRL.