This study identified systematic differences between therapists (n = 114) and patients (n = 119) in the process components that predict evaluation of psychotherapy sessions. The Comprehensive Scale of Psychotherapy Session Constructs was developed to measure 9 process variables and their relationships to session evaluation from the perspectives of therapist and patient. Regression equations predicting session evaluation from the process components for the 2 groups were significantly different. Therapist session evaluation was best predicted by therapist expertness, and patient session evaluation was best predicted by the therapist real relationship. The therapist real relationship negatively predicted therapist session evaluation when all process variables were considered simultaneously. Patient progress and patient involvement significantly and positively predicted both therapist and patient evaluation.