Transnational policy networks (TPNs) participate in global governance by formulating ideas and policy options around and through formal and informal intergovernmental organizations. They illustrate the third type of informal governance introduced in Chapter 1, informal governance that exists in the spaces around these institutions. TPNs are constituted by individuals who share a common expertise, a common technical language, and broadly shared normative concerns, but not a common institutional setting nor agreement on specific policy goals. This chapter contrasts TPNs with other institutional forms in the literature – advocacy networks, epistemic communities, transgovernmental networks, public–private partnerships, multistakeholder initiatives, and transgovernmental initiatives – and argues for their integrative advantages and ability to address individual agency and power. A heuristic case illustrates how a TPN functioned to create the Office of the Ombudsperson at the UN – securing rights protection for individuals targeted for UN sanctions – despite the initial opposition of all five Permanent Members of the Security Council. The chapter concludes with reflections on the potential benefits of applying the concept to other emergent policy domains.