The current study examined the moderating effect of impulsivity on the relation between anger and adolescent problem behavior (substance use and delinquency). High levels of anger were associated with delinquency for impulsive, but not for nonimpulsive adolescents in cross-sectional analyses. This moderating effect was not supported for substance use. Gender-moderated links between temperament and problem behavior showed that anger predicted substance use for females only, and impulsivity was more strongly associated with delinquency for males. In prospective analyses, both anger and impulsivity predicted adolescent problem behavior, but impulsivity did not moderate the effects of anger. Overall, results provided partial support for the notion that temperament dimensions operate interactively to promote poor adjustment.