Friendship is another major theme in Holes. Before Stanley goes to Camp Green Lake, he doesn't have any friends. He is overweight and is larger than his classmates. As a consequence, he is picked on and teased. Stanley is a misfit and he knows it. Between his low self-esteem and bad luck, Stanley is quite unhappy. After being at Camp Green Lake for a few weeks, Stanley realizes he is larger than the boys in his tent, but he is no longer fat — the shoveling has strengthened his muscles. The boys respect his size and give him the nickname "Caveman." A bond develops between Stanley and the boys. He gives X-Ray the lipstick tube he finds and takes the blame for Magnet when he stole Mr. Sir's sunflower seeds. Stanley understands the hierarchy that exists amongst the boys; consequently, they learn to trust Stanley.
Stanley and Zero form a close friendship. Zero trusts Stanley enough to reveal that he can not read or write. Stanley doesn't laugh at him. Instead he begins to teach Zero how to read and realizes that Zero is quite intelligent. Zero fights for Stanley and after he runs away, Stanley worries about him until he realizes his only choice is to go find him. Stanley's yearning to rescue Zero empowers him to carry Zero up the side of the mountain. Sitting on top of the mountain, Stanley is happy. He likes the person he has become and he feels good because he has a friend.
Another theme that is evident in the novel is family relationships — Stanley has a loving family and Zero has no family. Racism is evident when Sam the Onion Man and Katherine Barlow are punished because they have an interracial relationship and when Zero is called Stanley's "slave" by the other boys when he digs half of Stanley's hole. The influence of the environment on the actions of people is evident when the extreme heat and lack of shade anywhere makes the boys' "blood boil." Finally, a theme that Sachar revisits in other books is evident. That theme is the compassion for society's underdogs. Stanley and Zero are misfits, but when given the opportunity to prove themselves, they exhibit their strengths and rise above the negative judgments others make about them.
