Intelligence is an important general cognitive ability that influences learning and life adjustment; yet, it does not work in isolation in affecting human development. Multiple factors, such as personality and context, can work in tandem with individual intelligence to impact outcomes. Although the literature has demonstrated clear relations between intelligence and school adjustment, particularly academic achievement, surprisingly little research has been conducted to explore how social and personality factors may play a role in shaping the relations. Thus, the purpose of this study was to examine how social competence moderates relations between IQ and measures of school adjustment. Participants in the study included 261 Chinese children (138 boys, 123 girls) from Jintan, China. Data were collected from multiple sources. Children’s IQ was assessed using the Wechsler Preschool and Primary Scale of Intelligence during their last year of kindergarten. In a follow up study when participants were in fourth grade, peer assessments were measured to assess their social competence. In addition, the participants were asked to report their self-perceptions of academic performance. Peer nominations and teacher ratings were used to assess school competence, learning problems, and peer preference. Information on academic achievement was obtained from school records. The results showed that IQ was positively associated with all measures of school adjustment more strongly in individuals with low social competence than in individuals with high social competence, demonstrating a protective role that social competence can play in the development of school problems among children who are relatively lower in intelligence. These findings have implications for researchers, teachers, and parents in promoting social skills among children for success in school.