Global benchmarks have grown exponentially over the last two decades, having been both applied to and developed by states, international organisations, corporations, and non-governmental organisations. As a consequence, global benchmarking is now firmly established as a distinct mode of transnational governance. Benchmarking chiefly involves the development of comparative metrics of performance, which typically take the form of highly stylised comparisons which are generated by translating complex phenomena into numerical values via simplification and extrapolation, commensuration, reification, and symbolic judgements. This process of translation takes what might otherwise be highly contentious normative agendas and converts them into formats that gain credibility through rhetorical claims to neutral and technocratic assessment. This politics of numbers has far-reaching ramifications for transnational governance, including the dimensions and effects of indirect power, expertise and agenda-setting, coordination, regulation and certification, and norm contestation and activism. This Special Issue draws upon an emerging literature to explore how and why benchmarks both align with and expand upon established models of International Relations theory and scholarship. It does so by critically examining the role of global benchmarks in key areas such as state ‘failure’, global supply chains, disaster management, economic governance, corporate social responsibility, and human development.