Background <p>The development of internalizing problems in early childhood can have long-lasting negative impacts on social adjustment. Parental sensitivity is known to play a critical role in shaping children’s social skills and psychological well-being. However, the degree of this influence can vary based on the child’s gender, guided by the principles of gender role theory.</p> Objective <p>This study aims to explore the mediating role of children’s social skills and the moderating role of gender in the relationship between maternal sensitivity and internalizing problems in Chinese preschool children.</p> Methods <p>A longitudinal design was used to investigate with 212 mother-child dyads in Shanghai, China. At Time 1 (T1, <i>M</i>_<i>age</i> =48.75), maternal sensitivity was assessed through mother-child interaction observation, and children’s internalizing problems was assessed through the mother’s self-report. At time 2 (T2, <i>M</i>_<i>age</i> = 60.28), mothers rate internalizing problems and teachers rate social skills.</p> Results <p>Maternal sensitivity at T1 significantly predicted lower internalizing problems at T2. Children’s social skills partially mediated the relationship between sensitivity and internalizing problems. Furthermore, child gender moderated the relationship between maternal sensitivity and social skills, with a stronger positive effect observed in girls.</p> Conclusion <p>The findings highlight the protective role of maternal sensitivity against internalizing problems through enhanced social skills, particularly for girls. This underscores the importance of considering child gender in parenting interventions and contributes to a deeper understanding of the cultural context in early childhood development.</p>