- Sammi Hanratty as Chrissa Maxwell
- Adair Tishler as Tara James
- Ariela Barer as Sonali Matthews
- Kaitlyn Dever as Gwen Thompson
- Shelby Harmon as Jayden Johnson
- Anika Borger as Amanda
- Annabeth Gish as Meg "Mom" Maxwell
- Timothy Bottoms as Paul "Dad" Maxwell
- Michael Learned as Louise "Nana" Hanlon
- Austin Thomas as Tyler Maxwell
- Joanne Baron as Mrs. Ziminsky
- Jennifer Tilly as Mrs. Rundell
- Don Franklin as Mr. Beck
- Jennifer Parsons as Janine Thompson
- Kaylin Stewart as Alexandra
- Christian Pikes as Joel
- Grace Rolek as Hayley
- Preston/Tyler Strother as Brock
- Ashley Ausburn as Rachel
Director: Martha Coolidge
Screenplay by: Christine Coyle Johnson and Julie Prendeville Roux
- In the movie, Sonali does not begin to regret her actions as a bully until she starts to befriend Chrissa. In the book, she is disturbed by the bullying from the start.
- Jadyn has straight, blonde hair and brown eyes in the movie, while in the book, she has brown, curly hair and jade-green eyes.
- In the movie, Tara is implied to be the cyberbully, while in the book, Tara is unaware of the cyberbullying, and Jadyn is eventually revealed to be the culprit.
- In the books, Sonali and Jadyn are on the swim team. Also in the books, Gwen is on the swim team, but switches to being assistant to Mr. Beck. In the movie, Sonali, Jadyn and Gwen only come to the meets.
- In the movie, the spelling of Jadyn's name is changed to Jayden.
- In the book, Chrissa is left-handed, while in the movie she's right-handed.
- In the book, Chrissa asks Mr. Beck to let her switch seats so that she can sit with Gwen and Sonali, and he grants her request. In the movie, Mr. Beck comes up with the idea himself after being asked about Chrissa by Mrs. Ziminsky, to which he replies that Chrissa is quiet, finishes all the work and is a good kid. She then tells him that she and he have to do something about Tara’s being a bully, and he agrees, saying that he has an idea; with that, he informs Tara and Jayden to switch seats with two other students, and then informs Gwen that he’s moving her to Cluster 4, where Chrissa and Sonali are sitting, much to her delight.
- In the movie, Starburst is born in winter. In the books, she is born in the summer. Also, Chrissa named her Starburst in the books because she just "burst into the scene", while in the movie, Chrissa and Tyler named her Starburst because their grandpa wanted to name it Starburst.
- Nana's cat, Keefer, Sonali's dad, Jadyn's parents, and Tara's mom aren't in the movie.
- In the books, Tyler's friend Joel is in Chrissa's class, in the movie it is shown he is not in her class.
- In the movie, Chrissa and Tara make a truce to allow their swim team to win. After this, Tara seems to reconsider her actions and try to reform. In the books, Tara takes the initiative to try to befriend Chrissa and Gwen, although she still accuses Chrissa of "stealing Sonali". There is no swim meet scene like in the film.
- Tara dares Tyler in the movie to get at Chrissa; in the books Tara and Chrissa are already friends when she dares Tyler. Chrissa prompts this by muttering that someone should teach him a lesson for boasting about his dive and Tara takes it up. However, she is not as malicious as she is in the film.
- The Solidarity Scarves only appear near the end of Chrissa, but they are more prominent in the movie.
- In the books, Tyler gets a concussion after he hit his head on the board; this is not present in the movie.
- Chrissa quits the swim team in the movie; this is not present in the books.
The movie premiered on HBO at 7:15 EST/PST on Monday, January 5th, 2009.
The DVD was released on January 6th, 2009 through the website and various retailers.
Items Associated With the Movie
- In the movie, Kaitlyn Dever's character, Gwen Thompson, played the violin. Clara Rosenberg's hands were filmed playing two songs that Gwen plays in the movie. The actual songs were pre-recorded by a third person.
- The Chrissa character was given the code name "Lulu" to prevent collectors and competitors from finding out too much about the release. "Lulu" is the name of the Chrissa movie's casting director's dog.
- Sammi Hanratty is shown wearing several American Girl outfits: the Chrissa meet dress, the Chrissa pajamas, the School Days outfit, Chrissa's Sundress, the I Like Your Style Outfit, and the Island Luau Outfit. Gwen is shown wearing the Licorice Play Outfit.