The goal of this chapter is to describe the authors' program of research evaluating a cognitive-behavioral group treatment approach for adolescent depression. Since 1982, their group has been involved in a major research effort to develop and test the efficacy and effectiveness of the Adolescent Coping With Depression Course (CWD-A). They begin the chapter by briefly reviewing psychosocial treatments for adolescent depression. Next, they review the rationale and theoretical background for their treatment approach, describe the CWD-A course and its companion course for the parents of depressed adolescents, and summarize results from two randomized clinical trials with 24-month follow-up. A clinical vignette is provided to illustrate the changes that have occurred with this intervention. To better understand the mechanisms of therapeutic change in depressed adolescents, they next address several issues related to treatment response. The authors conclude by describing more recent research with the CWD-A intervention and future directions. (PsycINFO Database Record (c) 2012 APA, all rights reserved)