What do Big Data do in Global Governance? Two paradoxes associated with Big Data are especially relevant to global governance. First, while promising to increase the capacities of humans in governance and elsewhere, Big Data also involve an increasingly independent role for algorithms, technical artifacts, the internet of things, and other objects, which can reduce the control of human actors. Second, Big Data involve new boundary transgressions as data are brought together from multiple sources, including clicks of web users and data flows from machine sensors, while also creating new boundary conflicts as powerful actors seek to gain advantage by controlling Big Data and excluding competitors. These changes are not just about new data sources for global decisionmakers, but instead signal more profound changes in the character of global governance.