This paper introduces a new dataset on transnational public-private governance initiatives (TGIs) in world politics. TGIs are institutions in which states and/or intergovernmental organizations cooperate with business and civil society actors to govern global problems. They have flourished since the late 1990s and, today, govern a broad range of global policy domains, including environmental protection, human rights, health, trade, finance, and security. Yet, existing research lacks the data necessary to map this phenomenon and its variation along dimensions, such as issue areas, governance functions, participation, and institutional design. The Transnational Public-Private Governance Initiatives in World Politics Data is designed for this purpose. It contains detailed information on the scope, functions, membership, and institutional design of 636 TGIs created between 1885 and 2017. I describe the sample generation and discuss coding rules. I also map the proliferation and characteristics of TGIs, and provide an exploratory analysis of the relationship between state participation in TGIs and domestic democracy to show how the new data contributes to enhancing ongoing debates in international relations. The paper concludes by discussing how the new dataset may be useful in future research on global governance.