This paper outlines key issues and provides insights to government leaders looking to design and implement initiatives that require joint working across public agencies. The first part of this paper defines key concepts and explores the benefits and related costs of cross-agency initiatives. The second discusses various contextual elements that need to be considered when making decisions about how to design cross-agency initiatives, including the nature of the objectives, the systems of government, and relationships among potential partners. The third section looks at different models across four fundamental elements: governance; people (team support), funding, and performance monitoring. The final section looks at some of the main systemic elements that can support cross-agency initiatives success.