New forms of medication and brief psychotherapy have dramatically changed how depressive disorders have been treated over the past two decades. In spite of these changes, the quality of treatment for depression remains poor at the population level. In this article, the authors review current concepts and theory regarding the quality of treatment for depression. They present a conceptual model of four points in the course of a treatment episode when clinicians could deviate from guidelines. Using the model, the authors review research that supports guideline recommendations and that can inform clinicians' decisions. They suggest several areas for future study and action, including extending awareness and recognition outside the medical care setting to schools and workplaces, addressing growing concerns about possible overtreatment, using qualitative research approaches to gain an understanding of patient perspectives on treatment, and improving the measurement for quality of treatment.