To what extent can crowdsourcing help members of civil society overcome the democratic deficit in global environmental governance? In this paper, I evaluate the utility of crowdsourcing as a tool for participatory agenda-setting in the realm of post-2015 sustainable development policy. In particular, I analyze the descriptive representativeness (e.g., the degree to which participation mirrors the demographic attributes of non-state actors comprising global civil society) of participants in two United Nations orchestrated crowdsourcing processes—the MY World survey and e-discussions regarding environmental sustainability. I find that there exists a perceptible demographic imbalance among contributors to the MY World survey and considerable dissonance between the characteristics of participants in the e-discussions and those whose voices were included in the resulting summary report. The results suggest that although crowdsourcing may present an attractive technological approach to expand participation in global governance, ultimately the representativeness of that participation and the legitimacy of policy outputs depend on the manner in which contributions are solicited and filtered by international institutions.