International humanitarian law is lauded as a civilizing force that seeks to limit the effects of war for humanitarian reasons. There is, however, an increasing sense that IHL has facilitated rather than restrained military operations by conferring undue legitimacy on violence in war. This article focuses on the nature of the relationship between legitimacy and IHL to ascertain whether this is indeed the case. It concludes that, while IHL alone cannot confer "normative legitimacy" on battlefield conduct, it does frame "empirical legitimacy." Whether such legitimacy is unwarranted is, ultimately, best judged by reference to morality. Yet insistence on the pre-eminence of humanitarian concerns within IHL is shown to be both misleading and aid social acceptance of battlefield conduct that humanitarians generally deem deficient.