The book was well received by critics. The New York Times wrote, "The Chocolate War is masterfully structured and rich in theme; the action is well crafted, well timed, suspenseful; complex ideas develop and unfold with clarity."
Children's Book Review Service said, "Robert Cormier has written a brilliant novel."
Cormier explained in an interview that he was "interested in creating real people, dramatic situations that will keep the reader turning pages." He went on to say that although some adults dislike the book because of the topics discussed, "the kids can absorb my kind of book because they know this kind of thing happens in life."
The New York Times Book Review declared, "Mr. Cormier is almost unique in his powerful integration of the personal, political and moral" and The Australian wrote that young readers "recognised his vision as authentic and admired his willingness to tell things as they are". However, the book has been banned from many schools and it was one of the most challenged books of 2006, for its sexual content, strong language, and violence.
Reviewers compared the book to A Separate Peace and Lord of the Flies.