Trauma is proposed as a key to understanding the development and persistence of adolescent conduct problems, in conjunction with other contributing factors. A trauma-focused individual therapy approach is presented as one example of how this population might be more effectively treated. This approach features motivational interviewing, self-control training, and trauma resolution, and integrates eye movement desensitization and reprocessing (EMDR). This chapter reports on an open trial of 6 adolescents with school and conduct problems who received school-based MASTR treatment. Reductions in post-traumatic stress, related symptoms, and problem behaviors, along with improved school performance, indicate the value of further study of this treatment approach.