Unlike a typical Future of Children issue, which describes what’s already known about a topic that affects children’s lives, this issue focuses on an approach to research and practice. We aim to distill lessons from existing ECE partnerships and to provide a road map for researchers and policy/practice leaders who want to collaborate. The articles examine both the challenges and the opportunities of partnership work, and show how partnerships may, in some instances and when carefully designed, pave the way for systems-level change. Each article is centered on a major challenge or opportunity, such as creating a research or funding agenda, developing tools, taking innovation to scale, navigating different timelines, finding a balance between rigor and feasibility, and building capacity. (author abstract)