Abstract Background: Evidence regarding the efficacy of psychotherapy in adolescents with borderline personality disorder (BPD) symptomatology has not been previously synthesized. Objective: To conduct a systematic review and meta-analysis of the randomized controlled trials (RCTs) in order to assess the efficacy of psychotherapies in adolescents with BPD symptomatology. Methods: Seven electronic databases were systematically searched using the search terms BPD, adolescent, and psychotherapy from database inception to July 2019. Titles/abstracts and full-texts were screened by one reviewer; discrepancies were resolved via consensus. We extracted data on BPD symptomatology, including BPD symptoms, suicide attempts, nonsuicidal self-injury, general psychopathology, functional recovery, and treatment retention. Data were pooled using random-effects models. Results: Of 536 papers, seven trials (643 participants) were eligible. Psychotherapy led to significant short-term improvements in BPD symptomatology posttreatment (g ¼ 0.89 [1.75, 0.02]) but not in follow-up (g ¼ 0.06 [0.26, 0.39]). There was no significant difference in treatment retention between the experimental and control groups overall (odds ratio [OR] 1.02, 95% confidence interval [CI], 0.92 to 1.12, I 2 ¼ 52%). Psychotherapy reduced the frequency of nonsuicidal self-injury (OR ¼ 0.34, 95% CI, 0.16 to 0.74) but not suicide attempts (OR ¼ 1.03, 95% CI, 0.46 to 2.30). Conclusions: There is a growing variety of psychotherapeutic interventions for adolescents with BPD symptomatology that appears feasible and effective in the short term, but efficacy is not retained in follow-up—particularly for frequency of suicide attempts.