<p>Guided by Stage-Environment Fit and Relational Developmental Systems frameworks, this three-wave study examined longitudinal, bidirectional associations between perceived school climate and the Five Cs (5Cs) of Positive Youth Development (PYD) among Chinese adolescents. Participants were a school-based open-panel sample of 2,350 students in Grades 10 and 11 recruited through schoolwide psychological screening in three public high schools in Shouguang City, China. The Delaware School Climate Survey-Student (DSCS-S) and Positive Youth Development-Very Short Form (PYD-VSF) were administered on three occasions approximately 4–5 months apart. Cross-lagged panel network (CLPN) models estimated conditional associations among school climate facets and PYD dimensions across adjacent school terms. From T1 to T2, the larger selected cross-domain associations were mainly from PYD Connection to later perceived school climate, including later lower bullying schoolwide, teacher-student relations, respect for diversity, clarity of expectations, and peer relations. From T2 to T3, PYD Connection again showed larger associations with later perceived school climate, and clearer climate-to-PYD associations also emerged: student-student relations were associated with later Confidence and Competence, and fairness of rules was associated with later Connection. Connection showed the largest bridge expected influence across both intervals, suggesting that students’ sense of connection and belonging was the most consistent cross-domain bridge in the estimated networks. Together, these findings point to relational connection as a key linkage between adolescents’ developmental strengths and their perceptions of school climate during the high school transition.</p>