The rules, policies and structures of International Institutions have consequences for women and the struggle for women’s human rights globally and within nation states. They are necessarily implicated in the achievement of gender justice. Increasingly, international institutions – conceived as international rules and as organisations – have been designed with clear gender justice mandates – such as in the case of UN Women and the International Criminal Court, while others such as the OECD and the World Bank are attempting to retrofit gender concerns into their operations. This panel asks how do international institutions understand and operationalise gender justice within their mandate? Legitimacy comprises both legal entitlement and more sociological understandings beyond legal compliance, which are based upon an acceptance of appropriateness and credibility. The panel explores how/have steps towards this goal shaped their legitimacy (in both positive and negative ways) as perceived by institutional designers and diverse stakeholders in the international system.