Leveraging data from a longitudinal study of Chinese families (n = 364), this research aims to understand the role of secure base script knowledge as a cognitive mechanism by which early caregiving experiences inform adolescents' friendship quality and feelings of loneliness. Results showed that observed maternal sensitivity at 14 and 24 months old was negatively associated with adolescents' self-reported conflicts with close friends ([beta] = -0.17, p = 0.044) at 15 years old, and this association was partially mediated by their secure base script knowledge assessed at 10 years old. Further, secure base script knowledge moderated the link between adolescents' friend conflict and feelings of loneliness ([beta] = -0.15, p = 0.037). The results support a cognitive script perspective on the association between early caregiving experiences and later socio-emotional adjustment. Furthermore, this study adds to the developmental literature that has previously focused on more stringent and authoritarian aspects of parenting in Chinese families, thereby contributing to our understanding of how sensitive and supportive parenting practices contribute to socio-emotional development outside of Western contexts.