The Booklist review called The Wednesday Wars “gentle” and “moving” because of the author’s voice. Kirkus Reviews says that the novel’s events unfold “in hilarious, heart-wrenching fashion,” and deems the portrait of the main character’s growth “masterful.” Judging from the extended review in the Journal of Adolescent & Adult Literacy, Jean Boreen would agree with all of those points, and add a couple more. Boreen discusses the plot in some detail and segues from this discussion into an analysis of the book’s sharp historical eye, suggesting that how the various characters in The Wednesday Wars dealt with the Vietnam War is historically accurate. Boreen argues that the novel is pedagogically useful for teaching children about the period. Hannah Trierweiler also recommends the book for use in the classroom, but primarily for the portrait of friendship, particularly that of Holling Hoodhood and Mrs. Baker.

Negative reviews of the novel are not common. However, Joel Shoemaker, discussing the book for the School Library Journal, found many weaknesses: the pacing is off, the tone “cloying,” and some of the chapters overly long. Shoemaker also found the book’s plot unlikely. Shoemaker’s criticisms, however, are definitely in the minority, as Liz Rosenberg, writing for the Boston Globe, specifically singled out Schmidt’s voice for praise (though she too found the pacing off, especially at the novel’s start). Those criticisms aside, all reviewers have praised the book’s sense of humor, and the awards committees agreed. The Wednesday Wars was a Newbery Honor book and a Printz Honor book.