Abstract
The fairplayer.manual is a manualized, school-based intervention program to prevent bullying and relational aggression. We present first results from an evaluation study conducted in Berlin (Germany) with 119 students (age 14-17) from a comprehensive school using a controlled pre-/post-/follow-up design. Utilizing standardized questionnaires we found a significant and practically relevant decrease in bullying behavior and in peer and teacher reported relational aggression in the intervention group after the fairplayer.manual was implemented.