Samantha "Sam" Kingston
Samantha "Sam" Kingston is the protagonist in the book. She is initially a mean girl, who follows the every whim of her three other best "mean girl" friends: Lindsay, Ally, and Elody. Sam is very popular, but very insecure as she herself has been a victim of bullying. The character develops a lot though the book, and her heart grows. In the end she is not the same person she was in the beginning of the book, as she learn a lot during the last day of her life.
Lindsay Edgecombe
Lindsay Edgecombe is the leader of the "mean girls" group. When she was younger, she used to bully Sam. She was also best friend with her current "main" victim, Juliet Sykes. She is very popular and has spent a lot of her time bullying others to remain on top of the social hierarchy.
Juliet Sykes
Juliet is a quiet character and has no friends. She was best friends with Lindsay, until Lindsay blamed her for an event she didn't commit, thus ending their relationship and making Juliet an outcast. She has the nickname of "psycho" and is constantly bullied. She decides to end her life by jumping in front of the "mean girls" car, thus committing suicide whilst killing her enemies.
Rob Cokran
Rob is Sam's boyfriend. They had been going out "since October, but I'd been in love with him since sixth grade..." our narrator, Sam, explains. He is a dumb jock who wants to get drunk and have sex with Sam. He isn't goal oriented and doesn't seem to genuinely care for Sam. She realizes this.
Kent McFuller
Kent was a childhood friend of Sam's and her first kiss, in the third grade. Sam is once viewed as off limits to Sam based on their history and partly because her friends expected her to date someone better in their opinion. Sam is reliable, trustworthy and helpful. He does all he can to help Sam.
