Objective: This study used a large U.S. population-based dataset to examine associations between childhood attention problems and adolescent substance use, sexual risk behavior, and delinquency. Methods: This prospective cohort study used data from the Future of Families and Child Wellbeing Study (n = 2,716). Bivariate statistics, multivariable logistic regression, and negative binomial models assessed associations between attention problems at age 9 years and subsequent use of cigarettes, alcohol, and marijuana, engagement in sex without a condom, and delinquency at age 15 years. Results: Nearly one-fifth (18.3%) of adolescents had elevated scores (more than 1 standard deviation above the sample mean) for attention problems at age 9 years. Adolescents with elevated attention problem scores in childhood were more likely than adolescents who did not have elevated scores to have ever smoked an entire cigarette (9% vs. 4%) and ever tried marijuana (24% vs. 20%). Elevated attention problem scores were associated with higher odds of ever having smoked an entire cigarette (adjusted odds ratio [AOR] = 2.06, 95% CI [1.39, 3.05], p < 0.01) and higher delinquent behavior scores (incidence rate ratio [IRR] = 1.30, 95% CI [1.11, 1.53], p < 0.01). In adjusted models, there were no significant associations between elevated attention problem scores and ever having tried marijuana, consumed alcohol, or engaged in unprotected sex. Conclusions: This study found that elevated attention problem scores in childhood were associated with higher risk of cigarette smoking and delinquent behaviors in adolescence. Results provide support for screening for attention problems among elementary school-age children and early intervention strategies to prevent health risk behaviors in adolescence.