The Multitheoretical List of Therapeutic Interventions (MULTI) assesses interventions from eight different psychotherapy orientations (behavioral, cognitive, dialectical-behavioral, interpersonal, person centered, psychodynamic, process-experiential, and common factors) and from the perspective of clients, therapists, and observers. The internal consistency for the subscales was moderate to high. Split-half reliability was moderate for clients and low to moderate for therapists and untrained observers. Interrater reliability for the subscales was low for untrained raters but moderate for psychotherapy-knowledgeable raters. A model of the MULTI subscales representing different psychotherapy orientations fit the data adequately but not parsimoniously in a confirmatory factor analysis. MULTI subscale levels successfully predicted sessions of different psychotherapy orientations. The MULTI seems to be a promising tool to investigate the interventions that occur in different psychotherapies.