Unfortunately, mean girls don't very often change. And even if they do, there might be another girl down the line. Even as an adult, I have had to deal with mean "girls" (who are now grown women). So it is vital that girls learn how to best deal with mean girls.
The book You Can't Sit with Us--Mean Girl Makeover by Nancy Rue is a young adult fictional book that follows the story of Ginger Hollingberry as a new student in the 6th grade. Kylie has it in for Ginger and even though there is a strict new anti-bullying code, Kylie manages to sneak under the radar and the bullying continues, in part via social media. Ginger is alienated from her friends and fears telling others what is going on because of threats from Kylie. It takes a serious situation for Ginger to finally let her father know what is happening. With the support of her friends, father and mentor, Ginger learns ways to cope with bullying and to feel more confident about herself.
This book, although fictional, covers the topic of bullying in a very accurate light. From fears victims may have from telling to sly ways bullies operate, the readers gain a better understanding of the topic. Most importantly, readers are presented with ways to not only cope with bullying, but ways to feel better about themselves. The book does bring in Christian elements, but is not so heavy that it would be a turn off to the reader. As this follows a 6th grade girl, I think the book is most appropriate for 5th-8th grade students. I would also suggest parents read this book. Reading the book together could be a springboard into conversations about real life situations.