This study examined the interconnections among preschool teachers’ self-efficacy, classroom process quality and children's social skill development based on a randomly selected sample of 5628 preschool children in a Chinese preschool context. Given the nested data structure, multilevel mediation modeling was utilized to investigate whether teachers’ self-efficacy, specifically teachers’ self-efficacy for instructional strategies (EIS), classroom management (ECM) and student engagement (ESE), exerted indirect effects on children's social skills through the mediation of classroom process quality measured by Pianta, Hamre and LaParo's (2008) Classroom Assessment Scoring System (CLASS) in three domains—emotional support (ES), classroom organization (CO) and instructional support (IS). Findings showed that CO is the only robust mediating mechanism between teachers’ self-efficacy and children's social skills, indicating the importance of teachers’ CO in developing Chinese children's social skills. Specifically, teachers’ CO acts as a positive mediator between teachers’ ECM and children's social skills, but a negative mediator between teachers’ ESE and children's social skills. This interesting negative mediation of teachers’ CO between teachers’ ESE and children's social skills offers insights into Chinese preschool classroom dynamics and child development. Findings and their implications are discussed in light of Chinese sociocultural features.