To justify their authority, international organizations (IOs) have long relied on a functional narrative that highlights effective problem-solving based on rational-legal expertise and neutrality. Today, IOs increasingly legitimize their authority in the language of democracy. Yet not all of them do so to the same extent, in the same manner, or consistently over time. In this article, we offer a comprehensive theoretical and empirical account of democratic legitimation in global governance. Our analysis builds on a new dataset, measuring the extent to which global IOs use democratic narratives in legitimizing their authority throughout the period from 1980 to 2011. The central findings are threefold. First, our data reveal a far-reaching rise of democratic legitimation in global governance. For many organizations, this increase remains relatively modest; for others, the democratic legitimation narrative becomes central. Second, this variation is mainly explained by a combination of two factors: (a) public visibility and protest constitute the driving forces of democratic legitimation and (b) IOs’ reaction to these legitimacy pressures unfolds in a path-dependent manner. Once organizations begin to take up democratic narratives, it seems to become costly to leave this path and shift to yet another set of norms. By contrast, the conventional wisdom that democratic legitimation follows in the footsteps of internationalized authority is not supported by our analysis.