Most studies of self-regulation involving children have linked it to specific outcomes within a single domain of adaptive functioning. The authors examined the association of self-regulation with a range of indices of adaptive functioning among 155 youth ages 8-18 years from families with very low income. Controlling for other explanatory variables, self-regulation was strongly associated with various outcome measures in the areas of mental health, behavior, academic achievement, and social competence. The authors also contrasted youths relatively high and low in self-regulation (the top and bottom quartiles). Youths with good self-regulation had much better indices of adaptive functioning across measures of social competence, academic achievement, grades, problem behaviors, and depression and anxiety than their counterparts with more diminished self-regulatory capacities. In addition, youths with better self-regulation skills stated more adaptive responses both in terms of how they coped with past stressful live events and how they would deal with hypothetical stressors. This study indicates that self-regulation is robustly associated with a range of important indices of adaptive functioning across many domains. Findings are discussed in light of their implications for theory and intervention for children of diverse economic backgrounds.