The findings show that self-control is intertwined with conduct problems and interpersonal deficits relatively early in life, and this nexus is fairly stable. The study identified five groups distinguished by levels and manifestations of self-control. Two groups, one large and the other of moderate size, had high self-control and low impairment and consisted mostly of girls. Two other groups, one large and the other moderate in size, had more moderate levels of impairment related to self-control, and differed from one another in gender composition. A fifth group was composed of kindergartners clearly identified by both parents and teachers as the most deficient in self-control. Relative to other children, they had lower functioning in motor and cognitive skills, interpersonal skills, and weaker approaches to learning. They were high in externalizing behaviors and lived in stressed family units. They were more likely to be boys and non-White. Findings from the multivariate procedure showed that parental stress, externalizing behaviors, interpersonal skills, and approaches to learning at waves 1 and 2 were associated with increased risk for diminished self-control and increased impairment across all groups. Implications are drawn for self-control theory and the broader study of youth violence. The study used data from the Early Childhood Longitudinal Survey-Kindergarten Class of 1998-99, which involved a nationally representative cohort of children drawn from approximately 1,000 kindergarten programs. Self-control was measured with a version of the Social Skills Rating Scale, which was completed by parents and teachers. Several scales were used across three waves in order to assess behavioral and interpersonal skills. 4 tables, 1 figure, and 48 references