Background: Emotional dysregulation seems to be a core feature of Borderline Personality Disorders (BPD). In addition, recent research in the adolescent population has shown that suicidal behaviours have been associated with maladaptive strategies of emotion regulation. Methods: This study examined the relative contributions of emotional dysregulation to suicide attempt history in a clinical sample of borderline adolescents. Data were analyzed from 85 participants of the Collaborative European Research Network on Borderline Personality Disorder. Participants completed measures of BPD traits and symptoms, suicide behaviours, emotional dysregulation, attachment styles and lifetime depressive disorders. Results: In an SEM model, lifetime depressive disorders and insecure attachment styles have a significant direct effect on lifetime suicide attempt, but only lifetime depressive disorders have an indirect effect through emotion dysregulation. The results suggest that emotional dysregulation has a mediating role in suicide attempts among BPD adolescents. Conclusions: These findings call for the development of interventions targeting the role of emotion dysregulation in effectively predicting and preventing suicidality in borderline adolescents.