Previous research has suggested that depressive disorders are common in youth and are associated with many negative outcomes. As a result, understanding how to treat depression effectively is very important. It is unclear; however, what factors predict treatment success or failure for depressed youth. Researchers are starting to investigate whether comorbid anxiety is a possible moderator of treatment outcome for youth with depression. Studies of the relation between comorbid anxiety and treatment outcome have produced mixed findings and have almost exclusively focused on older depressed adolescents. There is also limited research exploring whether parent intervention moderates the effect of comorbid anxiety on treatment outcome in depressed youth. This study focused on investigating the relation between comorbid anxiety and treatment outcome in a sample of 84 depressed female early adolescents who received either group cognitive behavioral therapy (CBT) or group CBT plus a parent intervention. The addition of parent intervention was explored as a moderator of the relation between anxiety and treatment outcome. Treatment outcome was measured by changes in depression severity and global functioning during treatment. The depression severity and global functioning scores of depressed girls with comorbid anxiety were also compared to depressed girls without comorbid anxiety prior to treatment to determine whether the first group of girls entered treatment with a different level of psychopathology. Participants and their primary caregivers were administered a semi-structured diagnostic interview which was used as a measure of depression severity, global functioning, anxiety severity, and to determine whether participants met diagnostic criteria for depressive and anxiety diagnoses. The results of this study suggested that depressed youth with comorbid anxiety or higher anxiety severity started out treatment with higher depression severity and lower functioning. Results also suggested that comorbid anxiety was not related to negative treatment outcome and that youth with comorbid anxiety actually experienced larger reductions in depression severity over the course of treatment than youth without comorbid anxiety. Parent intervention did not significantly moderate the effect of comorbid anxiety on treatment outcome. The study's limitations, implications of the results, and recommendations for future research were discussed.