Therapist response (countertransference) can be defined as the range of emotions a clinician experiences when interacting with a patient. Previous research has shown that this reaction plays an important role in the establishment of the therapeutic relationship, and that certain psychiatric disorders are systematically related to strong countertransference reactions in clinicians. For this study, 30 videotaped sessions were retrospectively analyzed by one observer using the Therapist Response Questionnaire (TRQ). The authors aimed to investigate the differences in therapist response between an adolescent case group consisting of 19 patients diagnosed with a cluster B personality disorder (PD), and a control group composed of 11 adolescents diagnosed with anorexia nervosa. The PD group scored significantly higher on the hostile/mistreated, helpless/inadequate, disengaged and overwhelmed/disorganized factors. This study adds evidence to the preexisting empirical literature on therapist response in regard to personality disorders and emphasizes the continuing need for recognition of countertransference across all psychotherapy orientations.