The potential efficacy of psychosocial interventions in the treatment of borderline personality disorder (BPD) is impacted by significant treatment non‐completion (TNC), with meta‐analytic studies reporting rates of attrition of between 25% and 28%. Increasing patient retention could facilitate outcomes and improve resource utilization, given limited healthcare services. A systematic search of PsycINFO, CINAHL, EMBASE, CENTRAL, and Web of Science Core Collection identified 33 articles that met the criteria for inclusion. Although substantial heterogeneity in terms of methodology and quality of analysis limited conclusions that could be drawn in the narrative review, a few consistent patterns of findings were elucidated, such as Cluster B personality disorder comorbidities and lower therapeutic alliance were associated with TNC. Interestingly, the severity of BPD symptoms was not a predictor of TNC. These findings are discussed in terms of their potential theoretical contribution to TNC. Clinically, there may be value in applying mindfulness and motivational interviewing strategies early on in treatment for individuals who present uncertainty about engaging in treatment. Further research to develop this empirical landscape includes focusing on high‐powered replications, examining burgeoning lines of research, and investigating dynamic predictors of TNC.