Personality theorists and practicing clinicians agree that high levels of interpersonal dependency play a role in Borderline Personality Disorder (BPD), and this link has been codified in several editions of the Diagnostic and Statistical Manual of Mental Disorders (DSM). Although there is widespread agreement that dependency is linked to BPD, there has never been a systematic review of empirical evidence bearing on this issue. This article reviews research in three areas: (1) the comorbidity of Dependent Personality Disorder (DPD) and BPD; (2) the association between trait dependency and BPD; and (3) differences in free-response (i.e., Rorschach) dependency scores in BPD and non-BPD patients. Results support DSM assertions of DPD-BPD comorbidity, confirm that high levels of trait dependency are associated with BPD traits and symptoms, and show that high levels of implicit dependency needs are present in BPD-diagnosed inpatients, but not BPD outpatients. Theoretical, clinical, and empirical implications of these patterns are discussed.