In new research appearing in the Annual Review of Developmental Psychology, a team of authors, with funding from the Duke Population Research Center, reviews how analyses of population-level administrative data—data on individuals’ interactions with administrative systems (e.g., health, criminal justice, and education)—have substantially advanced our understanding of life-course development. In the review, the authors focus on five areas where research using these data has made significant contributions to developmental science: (a) understanding small or difficult-to-study populations, (b) evaluating intergenerational and family influences, (c) enabling estimation of causal effects through natural experiments and regional comparisons, (d) identifying individuals at risk for negative developmental outcomes, and (e) assessing neighborhood and environmental influences. Further advances will be made by linking prospective surveys to administrative data to expand the range of developmental questions that can be tested; supporting efforts to establish new linked administrative data resources, including in developing countries; and conducting cross-national comparisons to test findings’ generalizability. New administrative data initiatives should involve consultation with population sub-groups including vulnerable groups, efforts to obtain social license, and strong ethical oversight and governance arrangements.