Chapter 3 addresses the potential for norm conflict arising from the parallel application of investment treaties and international humanitarian law. It argues that such conflict must be avoided through treaty interpretation. Drawing from their interaction with human rights law, the rules of armed conflict should inform the meaning of investment treaty clauses through ‘systemic integration’. The chapter shows that investment tribunals possess the authority and duty to conduct such a subordinate examination under humanitarian law as part of the interpretive exercise. Although standards of protection may, as a result, be lower than in peacetime, the chapter argues that giving effect to humanitarian rules through investment law ensures the normative appeal of investment treaties. It allows taking into account military concerns and rejects special treatment of foreign investors compared to ‘ordinary’ civilians. At the same time, the chapter highlights, investment treaties give investors a unique opportunity to enforce international rules during armed conflict and secure compensation for unlawful conduct in hostilities.