Based on the data collected in Uganda, Nepal, and Ethiopia, the papers included in this supplement fill a critical gap in evidence regarding multisectoral National Nutrition Action Plans. The studies offer new data and new thinking on how and why governance, effective financial decentralization, and improved accountability all matter for nutrition actions in low-income countries. This introductory paper offers an overview of the current state of evidence and thinking on the multisectoral nutrition policy cycle, including how governance and financing support that process. It also explores the benefits of applying a systems lens to understand the dynamic, enabling processes of the policy cycle - from research to knowledge and ultimately action - and to provide more dynamic and accurate information for nutrition advocacy and evidence-based decision-making. It concludes with key findings from the 5 country-level studies included. Several important themes emerge: the egregious gap in human resources needed for effective nutrition actions in most low-income settings, the value of research on bottlenecks and successes, and the need for routine monitoring of national policies and plans to measure their effectiveness in achieving both their own stated goals and global sustainable development goals. Reviewing these studies together provides a path forward in building stronger, evidence-based multisectoral nutrition policies and supporting implementation of the nutrition activities included within them.