No legal system deserving of continued support can exist without an adequate theory of justice. A world trade constitution cannot credibly exist without a clear notion of justice upon which to base a consensus. This paper examines two accounts of fairness found in moral philosophy, those of John Rawls and Tim Scanlon. The Rawlsian theory of justice is well-known to legal scholars. Scanlon's contractualist account may be less well-known. The aim of the paper is to start the discussion as to how fairness theories can be used to develop the tools for examining international economic policies and institutions. After elaborating the basics of the Rawlsian and Scanlonian accounts, the paper sketches how those accounts might be used to further our understanding of the fairness of World Trade Organization policies and institutions. In particular, it uses Rawlsian and Scanlonian accounts to assess whether the TRIPS Agreement is fair in how it deals with access to affordable medicines by persons in low-income countries.