This chapter situates contemporary developments in the policy and practice of business and human rights within a broader theorization of the concept of responsibility in world politics. By adopting a periodization that stretches back to the colonial era, it challenges common assumptions about what is truly new and/or ‘rising’ within this field of practice. The chapter first develops a theoretical distinction between discretionary and nondiscretionary responsibility; relates this distinction to questions of authority; and shows how responsibility can be viewed as simultaneously moral, political, and legal. Second, the chapter historicizes the practice of business and human rights across four governance models: colonial, sovereignty-based, neo-liberal, and ‘global governance’. Third, the chapter uses the conclusions of the first two sections to analyze the most significant contemporary policy initiative in this field: the UN Guiding Principles on Business and Human Rights (UNGPs). The UNGPs are consequentialist and assign responsibilities that are both legal and moral in nature, but they underemphasize political responsibility.<p></p>