Purpose <p>This study explored the associations between adverse childhood experiences (ACEs), emotion regulation, and mental health in adolescents and whether these associations differed by gender.</p> Method <p>Based on surveys collected from 8,704 seventh-grade students (12- to 13-year-olds) in Taiwan, we used PROCESS (Models 4 and 59) to examine associations among ACEs, emotion regulation strategies (cognitive reappraisal and expressive suppression), and depressive symptoms, as well as potential gender differences in these associations.</p> Results <p>Higher levels of ACEs were associated with lower use of cognitive reappraisal and greater use of expressive suppression. Both lower cognitive reappraisal and higher expressive suppression were related to higher levels of depressive symptoms. The associations among ACEs, expressive suppression, and depressive symptoms were stronger for females than for males, whereas no significant gender differences were observed in the associations containing cognitive reappraisal.</p> Conclusions <p>Emotion regulation played a critical and gendered role in the relationship between ACEs and depressive symptoms. The results hold implications for mental health services for youth, highlighting the importance of tailoring interventions so they uniquely address the ER capacities of both male and female youth who have experienced ACEs.</p>