Internalizing symptoms such as withdrawn and anxious-depressed behavior are common in adolescence. This prospective longitudinal study helps to gain insight into the development of internalizing behavior, focusing on the role of early parent–child interaction while ruling out genetic similarity as a confounder. More specifically, the central question addressed in this study was whether parental sensitivity and child inhibited temperament predict children’s withdrawn and anxious-depressed behavior in middle childhood and adolescence. We followed 160 early-adopted children (53 % girls) from infancy to adolescence. Structural equation modeling was used to test relationships both prospectively and concurrently. The results revealed that more sensitive parenting in infancy and middle childhood predicted less inhibited behavior in adolescence, which in turn predicted fewer internalizing problems in adolescence. The findings suggest that maternal sensitivity lowers adolescents’ inhibited behavior and decreases the risk for adolescents’ internalizing problem behavior indirectly through lower levels of inhibition. Supporting sensitive parenting in the years before adolescence may protect children from developing inhibited behavior and internalizing behavior problems in adolescence.