Early childhood is a critical period for developing food preferences and dietary patterns. Despite dietary recommendations to limit or eliminate sugary drinks in early childhood, children ages 0 to 5 frequently drink these beverages. There is currently a lack of evidence on effective policy, systems, and environmental strategies to reduce sugary drink consumption and provide and promote water among children ages 0 to 5. This national research agenda outlines research gaps and opportunities for researchers, foundations, and practitioners to pursue in order to reduce sugary drink consumption and increase safe water access and consumption among 0- to 5-year-olds. Thirteen key issues emerged as priorities for future research efforts. Identified research gaps included a limited baseline understanding of consumption patterns and recommendations in this age group, access to and promotion of different beverages in various settings, and addressing social determinants of health. By addressing the questions in this national research agenda, stakeholders can guide the field toward understanding how to significantly impact beverage consumption patterns, and ultimately health and well-being among 0- to 5-year-olds.