Although poor parental supervision has been associated with an increased adolescents' propensity for risk-taking behavior, few researchers have investigated nuanced mechanisms of how and for whom from the perspective of "family × school." Inspired by ecological system theory and self-control theory, this study aimed to investigate the mediating role of self-control and the moderating role of school climate between the link between poor parental supervision and risk-taking behavior.Four hundred and ninety-one Chinese adolescents (231 females, Mage = 15.39 ± 1.36) were recruited to participate in a three-wave longitudinal study (3 months apart) and complete questionnaires regarding poor parental supervision (W1), school climate (W1), self-control (W2), and risk-taking behavior (W1/W3).After controlling for W1 risk-taking behavior, our moderated mediation model indicated that W1 poor parental supervision was positively related to W3 risk-taking behavior by restraining the development of W2 self-control. Additionally, a high level of school climate as a protective factor buffered the negative impact of poor parental supervision on adolescents' self-control, further reducing risk-taking behavior.Our findings shed light on the processing mechanisms between poor parental supervision and risk-taking behavior among Chinese adolescents and underscore the importance of effective preventions and interventions to facilitate adolescents' healthy development.