Similarities: Both the book and the movie take place on the east coast of Pittsburg Pennsylvania. Part of the setting takes place in Rachel's room, Greg's house, and their school in both the book and the movie. Most of the scenes in the book and movie are very similar and consists of the same details.
Differences: In this movie, Greg hates eating in the lunchroom, because he fears that he will be alone and will not have anyone to sit with. In the movie, Greg and Earl get in a fight, so Greg refuses to eat with him, and eats in the cafeteria. In the book Greg deals with Earl and they eat together in Mr. Mccarthy's room.
Similarities: In both the book and the movie, Greg's character is portrayed very alike, with very few differences if any, and most of the things he says are the exact same. Rachel's mom is also a very similar character who seems to love Greg and is so thankful that he comes over to keep Rachel company. The rest of Greg's family is the same as the book, his dad being a stay at home dad who is lazy and walks in his pajamas all day long. Greg's mom is very protective and likes to be involved in Greg's everyday life.
Differences: Some differences are that in the book, Greg's sisters are mentioned multiple times, and then in the movie, they don't come up once, and we know nothing about them. Also in the book, Earls mom is described as someone who isn't involved in her child's life, and she doesn't seem to want to be. In the movie we don't see her mom once, and she isn't mentioned, so we know nothing about her.
Similarities: Some similar things in the plot between the book and the movie were that Greg and Earl liked to consider themselves as "co-workers" instead of friends. Also in the book and the movie, Earl pretends that he doesn't have any specific friends, because he likes to be friends with everyone so he has advantages that people in a certain group wouldn't. Also in the plot, Earl and Greg make mockery movies of other films, and they change them up and create shorter versions. Greg and Earl gather a group of people to make a film for Rachel saying how proud they are of her battling her cancer.
Differences: In the book, when Earl and Greg make the movie, they get a ton of people to leave a special message for Rachel, however in the movie they work on the film multiple times and can't seem to get it right. Another difference in the movie and the book in the plot is when Earl and Greg take Rachel out for ice cream in the book, but in the movie they take her out for popsciles instead.
Similarities: In both the book and movie, Rachel dies of lukemia in the hospital. She was diagnosed towards the beginning of the plot, and at the end if the movie, she ends up going into a coma and never wakes up. She goes into the coma while she is watching the video that was made for her, then she passes away. In the end of the book and the movie, Greg is shocked about Rachel's reaction to the film and was expecting her to be thankful for all the work he put into it.
Differences: Some differences in the resolution between the book and the movie were very slight. In the movie Earl went to present Rachel with her movie and watched it with her in her hospital bed. In the book however, Earl left the hospital and let Rachel watch it on her own. In the movie, Earl also brought Rachel a corsage on prom night while he as dressed in a tux, however in the book he did not.