We examined interpersonal variables as moderators of the relation between therapists' use of cognitive change (CC) strategies and CC in a sample of 125 adults who participated in cognitive behavioral therapy for depression. We measured self-reported maladaptive personality characteristics, interpersonal problems, and social skills at intake. Observers rated therapist adherence to cognitive methods for the first five sessions. Patients reported in-session CC following each session. Cognitive methods predicted greater CC. The relation between cognitive methods and CC was moderated by maladaptive personality traits; this relation was stronger for patients with greater maladaptive personality traits. We encourage future research investigating moderators of therapist interventions of putative therapeutic mechanisms.