["Journal of Research on Adolescence, Volume 36, Issue 3, September 2026. ", "\nAbstract\nInvestigating adolescents' dynamic emotional responses to stressors is critical in understanding how their psychological symptoms develop. However, prior research has primarily examined either adolescents' emotional reactions to daily stressors or major life events. This study bridges this gap by focusing on exams—a naturalistic, high‐stakes, and common stressor—and how parental emotional socialization shapes late adolescents' dynamic emotional experiences during exams and subsequent psychological symptoms. Participants were 216 Chinese late adolescents (Mage = 19.11 years, SD = 0.95 years; 80.8% female). At baseline, students reported parental emotion socialization and anxiety and depression symptoms. They were then surveyed three times across the exam period for their negative emotions. Six months later, anxiety and depressive symptoms were reassessed. Using latent change score models, results showed that maternal unsupportive emotion socialization was associated with adolescents' greater anxiety and depressive symptoms via heightened pre‐exam negative emotion reactivity, whereas maternal supportive emotion socialization predicted fewer anxiety symptoms via stronger down‐regulation of negative emotions during the exam week. These findings highlight that dynamic emotional changes in response to normative, high‐stakes stressors reflect vulnerability to psychological maladjustment and underscore the continuing influence of mothers in shaping the emotional experiences and mental health of Chinese late adolescents.\n"]