This article makes the theoretical case for a civil society-initiated Global Peoples Assembly (GPA) that would be popularly elected by the global citizenry. The authors argue that if civil society organizations were able to agree on a framework for a GPA and to hold popular elections, the assembly would be poised to become a singularly influential global institution. Exploring the dynamics of democratic legitimacy, and how it acts to empower political institutions, the article explores how an unofficially created GPA could gradually assume law-making powers.