Dialectical Behavior Therapy (DBT) is a comprehensive, multimodal cognitive behavioral treatment originally developed for individuals who met criteria for borderline personality disorder (BPD) who displayed suicidal tendencies. DBT is based on behavioral theory but also includes principles of acceptance, mindfulness, and validation. Since its development, DBT has been adapted to various populations and has been successfully used in a wide array of settings. This article presents the approaches used in DBT with a particular emphasis on (a) the philosophy and assumptions on which the treatment is based, (b) the major theoretical constructs and the DBT conceptualization of the client, (c) the intervention and specific techniques used, (d) research supporting the theory and treatment, and (e) the integration of diversity, culture, and social justice. (Contains 1 table.)