In this chapter, I draw on recent scholarship on the alleged legitimacy deficits in global governance institutions, seeking to engage the notions of legitimacy this literature suggests with the intriguing case of international human rights institutions. First, I reconstruct how this literature views the problem of legitimacy in global governance, a view that relies on a particular notion of international institutions which both explains and justifies global governance institutions in terms of the collective goods they help states obtain. The puzzle of legitimacy, on this view, lies in offering citizens valid reasons to obey, support or abstain from interfering with global governance institutions – reasons that include certain procedural, epistemic and substantive elements, which together comprise a complex, hybrid standard of legitimacy. Second, I explore to what extent this view of legitimacy problems in global governance institutions can be applied for analyzing corresponding legitimacy problems in international human rights institutions. Drawing on recent liberal international scholarship, I discuss the ways in which international human rights institutions constitute a different kind of political entity than typical global governance institutions. Uniquely, international human rights institutions do not help states obtain any joint benefits, but regulate the internal relation between a government and individuals under its jurisdiction, and, to the extent that they are effective, chiefly rely on domestic mechanisms of enforcement. This crucial difference between the two kinds of international institutions, in turn, changes the legitimacy puzzle involved. In the human rights area, the problem of legitimacy rarely entails offering citizens reasons why they should accept to bear the costs of international cooperation in light of the benefits it provides for states. Rather, the issue is why governments should accept their obligations under international human rights law, in light of the benefits human rights treaties provide for citizens. In the third section, I draw out the implications of this analysis for finding such reasons. While the complex, hybrid standards of legitimacy suggested for global governance institutions seem difficult to transpose to international human rights institutions, the discarded notion of state consent provides an essential component of legitimacy for the human rights area. Finally, I discuss whether the notion of international institutions discussed in the chapter may have implications beyond the human rights area.