Purpose: The measurement of Gottfredson and Hirschi's (1990) concept of self-control has received significant attention. However, research has not yet compared and explored the implications of using self-reported versus other-reported measures of self-control. Addressing this gap is the goal of the present study. Method: Using data drawn from a sample of U.S. families across 10 cities, the current study uses structural equation models to examine whether identical indicators of maternal and adolescent reports of self-control are differentially related to delinquency and parental socialization. Results: Two key findings emerged. First, the strength of the relationship between self-control and delinquency is substantively weaker when maternal reports are used in lieu of adolescent reports. Second, a comprehensive measure of parental socialization--capturing dimensions of monitoring, hostility, and warmth--is strongly related to adolescent reported self-control but only weakly related to maternal reported self-control. Conclusions: These findings suggest that substantive conclusions about the strength of the relationships between self-control, delinquency, and parenting are dependent on the source of the measure of self-control.