Research Findings: This study aimed to explore the mediating role of social competence and the moderating role of teacher-child conflict in the relation between maternal overcontrol and Chinese preschooler's internalizing problems. Participants were 216 children aged 3-4 years, from two kindergartens in Shanghai, China. Mothers completed the observation of mother-child interaction task. Teachers completed the assessment of children's social competence, internalizing problems, and teacher-child conflict. Result of mediation showed that maternal overcontrol indirectly predicted child internalizing problems through its negative association with child social competence. Moderated mediation results show that teacher-child conflict moderated the relation between maternal overcontrol and child social competence. Moreover, lower levels of teacher-student conflict can buffer the negative impact of maternal overcontrol on child social competence, and thus reduce children's internalizing problems. Practice or Policy: Maternal overcontrol as a negative parenting is related to children's maladjustment in current China. Reducing teacher-child conflict might alleviate the negative effects of maternal overcontrol on child social adjustment.