The goals of the current study were to examine whether children's social problem solving (SPS) skills are a mechanism through which temperament influences later academic achievement and whether sex moderates these associations. The participants included 1117 children enrolled in the National Institute of Child Health and Human Development Study of Early Child Care. During preschool, mothers and childcare providers rated children's temperamental shyness and inhibitory control, and SPS was assessed using a hypothetical–reflective measure during a laboratory visit. During kindergarten and first grade, teacher-report of math and language skills was collected. The results indicated that high ratings of inhibitory control in preschool, but not shyness, predicted better kindergarten and first-grade academic skills. Furthermore, children's SPS competence mediated the relations between both shyness and inhibitory control on later academic skills. The child's sex did not moderate these associations. The results suggest that preventative efforts targeting early SPS skills may buffer against later academic adjustment problems among temperamentally extreme children.