International courts play a key role in the attainment of global social justice objectives. The core contributions of international adjudication to global social justice are, not surprisingly, in line with the core functions of adjudication: the enforcement of substantive rights in a setting of fair procedures. Fully realizing the potential for justice inherent in this role is limited, however, by certain institutional and structural features unique to international adjudication. This article analyzes these opportunities, challenges, and background conditions in the context of international economic law (IEL) adjudication, where the results are mixed. For example, one can see in the case of the World Trade Organization (WTO) evidence of institutional and doctrinal evolution, albeit uneven, toward more substantively progressive outcomes. In the case of the foreign investment regime, however, one can see evidence of this regime retarding global social justice rather than advancing it. This makes it all the more important that all judges and arbitrators in IEL adjudications consider carefully the interpretive, remedial, and progressive roles that principles of justice can play in adjudication, particularly in the face of any deficiencies in procedural or substantive justice in the law or forum within which they operate. The work of IEL adjudication offers a number of possible sites for interpretive practices according to principles of justice, such as the resolution of disputes involves difficult interpretive questions centered around fairness and unfairness; equality and inequality of treatment; the scope of exceptions; and the meaning of evolutionary terms. Capitalizing on these opportunities and moving IEL adjudication toward global social justice requires what effective judging always requires: a vision of the goals of the institutions and regimes in question; an understanding of the social issues the regime either was created to address or touches incidentally through its actions and externalities; careful attention to the relationships among the relevant actors and their expectations; and a sophisticated understanding of the legal context and legislative history of the law in question.