War damages the bodies, lives and property of civilians. The same types of harm are caused by lawful as well as unlawful warfare. Lawfully committed harm originates from conduct in compliance with the laws of war, meaning proportionate and discriminate attacks and/or results from incidental damage that is not (clearly) excessive in relation to the expected military gains. Harm has been  unlawfully caused if it results from acts committed in breach of the laws of war. Victims of unlawful damages have a right to reparation, whereas victims of lawful damage – also referred to as collateral damage – do not. This thesis sets out to understand the reasons for this dichotomy, and tries to identify any possible grounds on which reparation to victims of collateral damage could be justified.