Often discussed alongside its critically acclaimed and more popular sequel, The Adventures of Huckleberry Finn, The Adventures of Tom Sawyer is generally thought by critics to be artistically a lesser work than Huckleberry Finn. Yet in spite of its shortcomings as a work of art, The Adventures of Tom Sawyer has remained popular around the world throughout the more than 120 years since its publication in 1876. Twain himself called this novel his "hymn to boyhood."

About Twain in general, Henry Nash Smith says that "there can be no doubt that Mark Twain was an artist of the people. His fresh handling of the materials and techniques of backwoods storytellers is the clearest example in our history of the adaptation of a folk art to serious literary uses." Walter Blair discusses in his article "Tom Sawyer" the novel's sources, both autobiographical and literary. Twain is widely known to have used people and places from his childhood in the writing of Tom Sawyer, and Blair also shows in his article that "Literary influences ... shaped both incidents and the overall pattern of Tom Sawyer." In his 1960 book Mark Twain, Lewis Leary refers to the fact that upon its publication, The Adventures of Tom Sawyer "placed Mark Twain once more at the head of best-seller lists." Leary states, "Probably no more continuingly popular book has ever appeared in the United States." Leary discusses the construction of the novel, claiming that although it seems "loose and shambling ... there is artistry in it also ... [and] ... perhaps because [Twain] worked long over it, this first independent novel is better constructed than any he was to write again."

Granville Hicks writes in The Great Tradition (1935) that The Adventures of Tom Sawyer starts out as seeming to be more than just a boys' book. Hicks believes that the novel begins as "a fine and subtle portrayal of the Missouri frontier." However, Hicks goes on to say that Twain's artistic powers were limited and that the book ends "in the tawdry melodrama of conventional juvenile fiction." In short, Hicks feels that Twain's book does not deliver on its promise. In Mark Twain: An Introduction and Interpretation, Frank Baldanza claims that Twain's reputation "is based firmly on the unparalleled achievement of his books about boys," namely The Adventures of Tom Sawyer and The Adventures of Huckleberry Finn. Baldanza calls Tom Sawyer "a delightful book," one that "gives a genial and warm-hearted backward glance at boyhood in Missouri" yet that also is "a serious and adult book." Baldanza sees the seriousness of the novel in the fact that "in the moral sphere, both Tom and Huck pay plentifully for their natural desires and impulses." John C. Gerber, in his book Mark Twain, acknowledges that "Tom Sawyer may not have the art or the profundity of Huckleberry Finn, but as an idyll of boyhood it has no peer anywhere." Gerber defends Tom Sawyer as a portrait of "boys as they are" and as a comic work. Like so many other critics, Gerber highlights the book's broad popularity, pointing out that Tom Sawyer "has been translated into over two dozen foreign languages and its sales, domestic and foreign, extend into the millions." According to Gerber, The Adventures of Tom Sawyer is second in popularity among Twain's books only to Huckleberry Finn.

Contemporary criticism about both Tom Sawyer and Huckleberry Finn often looks at the treatment of race and racism in these novels and the world they portray. While Huckleberry Finn has become controversial in some circles because of its use of language that degrades African Americans, Tom Sawyer does not offend in the same way, perhaps because slavery and its implicit racism exist more in the background of this novel than they do in Huck Finn. Shelley Fisher Fishkin points out in Lighting Out for the Territory: Reflections on Mark Twain and American Culture that "the Hannibal of Twain's youth, like the St. Petersburg of both Tom Sawyer and Huckleberry Finn, was a slaveholding society; but only in Huckleberry Finn would this fact struggle to the foreground. The world of childhood fantasy, play, and adventure had preoccupied him in Tom Sawyer." Fishkin sees none of Twain's growing "moral indignation" in Tom Sawyer, and she speculates that "Twain may have suspected that to recreate the boyhood pastoral of Tom Sawyer effectively, he had to suppress that troublesome thing called a 'conscience' that had begun to make him ask some difficult questions—such as whether that boyhood world was not so 'innocent' after all."