* Greg Gaines: The protagonist of the story. Greg is a high school senior who is more interested in filmmaking than anything else. He is awkward and struggles with social interaction, finding comfort in his friendships and his filmmaking.
* Earl: Greg's best friend, a fellow film enthusiast. Earl is more confident and outgoing than Greg, and he acts as Greg's partner in crime in their filmmaking endeavors. He is a source of humor and support for Greg.
* Rachel: A classmate of Greg's who is diagnosed with leukemia. She initially appears cynical and standoffish, but Greg and Earl develop a friendship with her as they try to make her a "feel-good" movie about her illness.
* Greg's Parents: While not central to the story, Greg's parents provide him with love and support, even when they don't fully understand his choices.
The novel primarily focuses on Greg's journey as he navigates his friendship with Rachel and confronts his own fears and insecurities. Earl is a vital part of this journey, acting as both a friend and a foil to Greg. Rachel's role is also crucial, forcing Greg to confront his own biases and learn the importance of human connection.