Methods: The efficacy will be tested in a randomized control group design with n=140 children. N=70 children will be treated in the first treatment phase (pre- to post1-assessment) of 16 weekly child-focused sessions with the treatment modules of ScouT. In the second treatment phase (post1- to post2- assessment) those children with sustained severe peer related aggressive behavior receive the comprehensive Treatment Program for Children with Aggressive Behaviour (Therapieprogramm für Kinder mit aggressivem Verhalten, THAV) which is a social competence training which combines patient- and parent-/teacher and peer-focused interventions with 16 child sessions and 6 parent-/teacher sessions. Those children with no severe peer related aggressive behavior receive 2 booster sessions of ScouT within a 16 week period.