In 2023, MOMENTUM Routine Immunization Transformation and Equity examined existing immunization toolkits and guidance to improve their uptake and use. MOMENTUM's Measurement, Adaptive Learning, and Knowledge Management Lab (MAKLab) conducted a desk review and key informant interviews, focusing on facilitators and barriers to immunization. Findings, including best practices and strategies, were synthesized into a list of factors influencing the uptake and use of immunization-related resources, considering similar non-immunization resources as well.