Models of developmental psychopathology emphasize both mediation and moderation processes among child and caregiving attributes; however, little research has examined both these processes simultaneously on the development of internalizing problems. This study tested a moderated mediation model that related early childhood shyness, emotion regulation and maternal negative control to school-age internalizing problems among 257 boys from low-income families. Shyness and maternal negative control was assessed at ages 1.5-2, emotion regulation was observed at age 3.5, and internalizing symptoms were assessed by mothers and teachers at age 6 or 7. Results indicated that 1) the active distraction regulation strategy mediated the relations between early shyness and maternal report of internalizing symptoms; 2) the passive/dependent regulation strategy mediated the relations between shyness and teacher report of internalizing symptoms; and 3) both mediation processes were moderated by maternal negative control. The results are discussed in relation to implications for early prevention and intervention.