Relational aggression is common among girls. It can be distressing for the victim and may not always be recognized as a form of bullying. This paper evaluates a school-based intervention designed to help girls understand relational bullying. Girls from a single-sex school completed a two-stage evaluation of the intervention. Students showed greater awareness of relational bullying after the intervention and indicated that it would influence them to change their behavior. At follow-up, retention of knowledge was good. Students reported greater self-monitoring of behavior and less exclusivity. While this is encouraging, we cannot conclude that all negative behaviors ceased. Implications and limitations of this study are discussed. (Published Abstract)