Since the Second World War, international law has greatly matured. Today, more than ever before, it and its institutions seem “real” – in other words, like domestic legal systems. Perhaps then, they can be brought into the domain of the comparatist. Of course, international law and its institutions are not quite the same as domestic legal systems and institutions. Great care must be taken by any comparatist embarking on a comparative analysis of international law, its sub fields or institutions. But, the great rewards of such an endeavor may be significant, both for the field or institution under review – and for comparative law itself. the author has previously considered international law from a comparative perspective, indeed from the perspective of a subset of comparative law, that of the Mixed Jurisdictions. There, it was argued that, when taken as a whole, international law was significantly akin to those Mixed Jurisdiction systems. The next step in the comparative analysis of international law is to apply a comparative analysis to specific fields and institutions within international law, seeking to identify and understand their legal cultures. Despite the fact that understanding the role of legal culture in international institutions is very important, it is not normally the subject of examination as it is not normally recognized as an issue by practitioners, officials or scholars. Indeed, it is not usually the subject of analyses by comparatists, who usually focus on domestic systems, and within those systems not as often on public law matters. Of course, given that most international law specialists are not comparatists and that most comparatists are not often knowledgeable or interested in international law, it is no surprise that this issue has generally been generally ignored. Yet, as the WTO and other international institutions become ever more “real”, there is a pressing need to study their legal cultures. This chapter, however, will not attempt to complete such a comparative analysis of any specific international sub field or institution. Instead, what it will attempt to do is to lay the groundwork for subsequent such analyses. In doing so, this essay will lay out a general framework, focusing specifically on the many questions that should be considered in any such analyses. To give life to this comparative exercise,the chapter shall use examples from an ongoing comparative analysis of an international institution, the World Trade Organization (the “WTO”) and its legal culture.