A substantial body of research has reported significant associations between children's levels of self-control and a variety of academic and behavioural outcomes. As a result, studies have begun to investigate the factors involved in the development of self-control. The current study builds on this body of research and examines the extent to which neuropsychological functioning and adversity influence the development of self-control from kindergarten to the end of fifth grade. Utilizing data from the Early Childhood Longitudinal Study-Kindergarten Cohort (ECLS-K), findings from the cross-sectional analysis revealed neuropsychological functioning to be significantly associated with the development of self-control, net of the presence of home, school, and environmental adversity. The longitudinal analysis revealed similar findings; however, home adversity surfaced as the most salient predictor of self-control during late childhood. Together, these findings highlight the importance of individual and environmental factors in the creation of children's self-control.