Therapist competence in assigning homework was used to predict mid- and posttreatment outcome for patients with Cluster C personality disorders in cognitive therapy (CT). Twenty-five patients that underwent 40 sessions of CT were taken from a randomized controlled trial (Svartberg, Stiles, & Seltzer, 2004). Therapist competence in assigning homework was rated by 2 independent raters assessing a session early in treatment (mostly Session 6) using the Cognitive Therapy Scale (CTS; Young & Beck, 1980). Higher ratings of therapist competence in assigning homework predicted a positive outcome at both mid- and posttreatment, even when controlling for initial symptom improvement. The results indicated that therapist competence in assigning homework is important for both symptom reduction and personality change in CT in the treatment of patients with Cluster C personality disorders. (Contains 2 tables.)