Judicial interpretation implicates a range of interacting social decision-making processes, including domestic, regional, and international political, administrative, judicial, and market processes – referred to collectively as institutions. In the case of the World Trade Organization (WTO), interpretive choices implicate the interaction of institutions for domestic, regional, and global governance. This article, which looks at the consequences of institutional choice in treaty interpretation by referring to examples from WTO case law, assesses interpretive decisions by examining how they allocate authority between different social decision-making processes. Focusing on the welfare and participatory implications of these choices, it offers two important conclusions, the first of which is that these choices impact upon social decision-making in terms of transparency, accountability, and legitimacy. Second, the choice of institutional alternatives – such as the incorporation of international standards, judicial balancing, delegation to markets, national deference, and process-based review – can determine which social decision-making process decides a particular policy issue, thereby affecting the institutional mediation of individual preferences.