This paper takes a theoretical approach to examining the justification for punishing child soldiers for war crimes. The author uses a wide range of academic literature from the field of Politics, Philosophy, Sociology, Media, Law and Psychology to explain this very complex issue surrounding child soldiers. The author is inspired by Omar Khadr's case, a young soldier who has been detained since he was at the age of 15, November 2002, in Guantanamo Bay and tried for alleged war crimes. The paper analyses this apparent breach of international law through an ethical lens with the hope that it can find a real justification for punishing child soldiers who commit atrocities. The author goes through controversial issues such as childhood being a social construct and children being rational moral agents, the diffusion of combatant's responsibility for war crimes and the moral justification of punishment. The aim of this paper is to launch an in-depth debate on a topic which might have been considered straight-forward, but as the author proves, it deserves the full attention of scholars in the field of Political Science and Law.