Over the last two decades, developmental science has made significant progress in understanding children's trajectories toward social-emotional and academic outcomes. At the same time, there has been dramatic growth in the design, implementation, and rigorous evaluation of school-based interventions to promote positive social-emotional development and/or academic achievement. The present study contributes to ongoing scholarship in the school-based prevention of social-emotional, behavioral, and academic problems by reporting three-year longitudinal, experimental impacts of a novel social-emotional learning and literacy development intervention (the 4Rs Program, "Reading, Writing, Respect and Resolution") on a cohort of 3rd grade children's social-emotional, behavioral, and academic functioning after three consecutive years of exposure to the intervention. The findings to date on the impacts of an integrated, social-emotional and literacy program provides clear evidence that this universal intervention has both broad impacts on social-cognitive processes and behaviors in the social-emotional domain, and targeted impacts in the academic domain. This study provides good evidence that universal school-based interventions, delivered to whole populations of children, can result in substantial impacts on children's developmental health and well-being. (Contains 1 figure.)