The linkages between self-regulation in childhood, risk proneness in early adolescence, and risky sexual behavior in mid-adolescence were examined in a cohort of children (N=518) from the National Longitudinal Survey of Youth. The possible mediating role of two early adolescent variables (substance use and negative peer pressure) was also examined. Self-regulation was assessed by maternal report at ages 8-9, and risk proneness, comprising aspects of sensation seeking and decision making, was assessed by adolescent self-report at ages 12-13. Structural equation models predicting risky sexual behavior at ages 16-17 indicated that self-regulation operated partly through early adolescent substance use, whereas risk proneness operated through early adolescent substance use and negative peer pressure. The overall model did not differ significantly for boys and girls, although there were gender differences in the strength of particular paths. These long-term longitudinal results support the importance of early self-regulation and risk proneness in setting the stage for adolescent sexual risk taking and implicate substance use and negative peer pressure as processes through which risk proneness and poor self-regulation lead to risky sexual behavior.