This study investigated the quality and development of the therapeutic alliance as a mediator of change in schema-focused therapy (SFT) and transference-focused psychotherapy (TFP) for borderline personality disorder. Seventy-eight patients were randomly allocated to 3 years of biweekly SFT or TFP. Scores of both therapists and patients for the therapeutic alliance were higher in SIFT than in TFP. Negative ratings of therapists and patients at early treatment were predictive of dropout, whereas increasingly positive ratings of patients in the 1st half of treatment predicted subsequent clinical improvement. Dissimilarity between therapist and patients in pathological personality characteristics had a direct effect on growth of the therapeutic alliance but showed no relationship with clinical improvement. The authors conclude that the therapeutic alliance and specific techniques interact with and influence one another and may serve to facilitate change processes underlying clinical improvement in patients with borderline personality disorder.