In many low- and middle-income countries, planning cycles and policy decisions are not always informed by cost evidence, even where relevant and recent cost evidence is available. The Immunization Costing Action Network (ICAN) project was a research and learning community designed to strengthen country capacity to generate immunization cost evidence and to understand and improve the evidence-to-policy linkages for the evidence. We identified key factors that increase the likelihood that health policy makers will use evidence for policy making or planning, which shaped the development of a 6-step evidence to policy and practice (EPP) facilitated process. ICAN used the EPP process in Indonesia, Tanzania, and Vietnam from 2016-2019. The experience resulted in several insights regarding country priorities related to cost evidence and factors that determine uptake. Cost evidence is more likely to be used if it answers a specific policy question prioritized by the immunization program, while the use case is less clear and urgent for routine planning and program management. Nonhealth ministries and subnational stakeholders can provide important perspectives to inform the research and its usability. The use case for evidence should be revisited periodically as divergences from formal planning cycles are common and new policy windows open. Ensuring evidence is available at the right time is critical, even if this requires a sacrifice between rigor and speed. Engaging a small group of stakeholders, rather than an individual, to champion the research may be more effective, and the research has greater legitimacy if it is produced by multidisciplinary country teams. Evidence and messages should be tailored for and packaged targeting different audiences. Going forward, continued support is necessary to bridge the divide between those who generate cost evidence and those who translate evidence for policy and planning decisions.