Since the 1980s, legal and political elites have increasingly formulated and used systems of indicators, including several systems developed for the purpose of measuring governments’ and corporations’ compliance with international labour rights and standards. Proponents of such metrics laud the ability of data-rich modes of regulation to displace rigid rules enforced by centralized agencies. The weakening of labour unions’ enforcement of workplace standards through collective agreements also spurs the use of indicators in the particular field of labour rights. This chapter describes the basic elements of labour indicator systems. It surveys prominent examples, such as those adopted by the ILO, the World Bank’s ‘Employing Workers Indicators’, those of the US National Academy of Sciences, various European labour indicators, and systems constructed by academic researchers. The chapter also discusses conceptual challenges to constructing and applying an indicator, such as framing, aggregation, and data inaccuracy. Labour indicator systems also pose deep normative questions. They are typically—though not inevitably—technocratic, centralized, and authoritarian, in the sense that the affected workforces or host-country electorates have little or no influence over the system. Indicator systems are generally produced by experts working on behalf of elites, with no or minimal democratic input. One can imagine more democratic, decentralized labour indicator systems, but their realization remains beyond the present political horizon.