OBJECTIVES: The aim of this study was to evaluate the potential moderator role of poor mentalization in the association between borderline personality disorder (BPD) traits and somatization, specifically focusing on the polarities of self- and other-mentalizing. DESIGN: This is a cross-sectional, general population study evaluating adolescents (n = 162, 61.3% female; ages 12-18, M = 14.63, SD = 1.02). The relationship between BPD traits and somatization was evaluated with self-mentalization (attention to emotions and clarity of emotions) and other-mentalizing as moderator variables. METHODS: One hundred sixty-two adolescents without serious mental health disorders were evaluated using self-report measures for borderline personality disorder traits (screening questionnaire for the Structured Clinical Interview for DSM-IV Personality Disorders (SCID-II), somatic symptoms using the Somatic Symptoms Questionnaire (SSQ), self-mentalizing using the Trait Meta-Mood Scale-24 (TMMS) and other-mentalizing using the Adolescent Mentalizing Interview (AMI)). Linear regressions were conducted to test the moderation effects of self- and other-mentalizing in the relationship between BPD symptoms and somatic complaints, controlling for age and sex. Moderation analysis was conducted using PROCESS version 3.5. RESULTS: The association between BPD symptoms and somatic complaints was moderated by a self-mentalizing dimension (emotional clarity) (b = -0.019, 95% CI = -0.0379 to -0.0002, p = .0476), but not other-mentalizing (b = 0.027, 95% CI = 0.000 to 0.053, p = .051). The effect of BPD symptoms on somatization disappears when emotional clarity is high, regardless the level of attention to emotions. CONCLUSIONS: Self-mentalizing appears to be an adaptive skill as it attenuates the relationship between BPD traits and somatization. Specifically, emotional clarity rather than simple attention to emotions is the aspect of self-mentalizing attenuating this association. These results support that self-mentalization is an important function in the management of body-associated emotions even in non-clinical levels of BPD traits. Findings suggest that strengthening self-mentalizing skills across development might contribute to resilience and salutogenesis.