To consider the role played by IHL in contemporary legal debate, this paper will first give a brief account of how this body of law interacts with other aspects of international law. As with other specialist fields, IHL is not absolutely settled; nevertheless, it is possible to broadly outline its place within the international legal order. This article aims to set a firm basis for considering what current discussions on the future of public international law can tell us about IHL and vice versa. Following an examination of the interplay between IHL and international law, this piece will turn to two thematic approaches that dominate current international legal discourse, namely, fragmentation and constitutionalisation. A brief outline of the parameters of both approaches is followed by an assessment of how each has engaged with IHL. The article concludes with some thoughts on how IHL could make a contribution to these debates. Ultimately, this article will discuss and propose how engagement from both ends of the spectrum would benefit international law and suggest why such connections should be encouraged.