Despite growing evidence for the efficacy of cognitive-behavioral therapy for insomnia (CBT-I), few data exist on the relation between process and outcome for this treatment. Drawing on interpersonal theory and the broader psychotherapy literature, this study examined the contribution of patient expectations and the therapeutic alliance to outcomes in group CBT-I. For patients with low early treatment expectations for improvement, those perceiving the therapist as higher in affiliation had greater reduction in sleep problems. Perceiving the therapist as critically confrontive was generally associated with less treatment satisfaction, and particularly so for those individuals who came to treatment with high expectations for improvement. Critical confrontation also differentiated dropouts from continuers, with dropouts experiencing their therapist as more critically confrontive.