Critics generally regard Ethan Frome as a departure from Wharton's usual subject matter. Wharton herself remarked that "it was frequently criticized as 'painful,' and at first had much less success than my previous books." The enduring popularity of the novel has somewhat cynically been attributed to its brevity and its place in the high school and college curriculum. Yet, wrote the critic R. Baird Shuman, it "remains a monument in the Edith Wharton canon." According to Allen F. Stein, the novel represents "the fullest treatment of the disasters that can occur when one attempts to leave even a repellent marriage." And biographer Cynthia Griffin Wolff calls Ethan Frome "a tantalizingly literary work."

At the time of the novel's publication in 1911, a review in the Nation praised the style as "assured and entirely individual." In a review titled "Three Lives in Supreme Torture," the New York Times Book Review reported that "Wharton has ... chosen to build of small, crude things and a rude and violent event a structure whose purpose is the infinite refinement of torture." The Saturday Review called the writing "singularly beautiful," but asserted that Wharton had gratuitously marred the work by allowing Mattie and Ethan to live. The review also made a point that other critics, particularly Lionel Trilling, would take up: "The end of Ethan Frome is something at which we cover the eyes. We do not cover the eyes at the spectacle of a really great tragedy."

Later critics found the novel too contrived and its characters unmotivated. Margaret B. McDowell was a dissenting voice, calling the characterization "subtle, strong, and masterful," and Richard H. Lawson called the characters Wharton's "best yet." To Blake Nevius, the novel counted for no more than a minor classic. J. D. Thomas took issue with the story's inconsistencies and what he called Wharton's fundamental ignorance of rural life and "uncertainty ... about the occupational concerns of men." He wrote, "It is regrettable that she felt obliged to narrate her story from the masculine point of view." R. Baird Shuman admitted that there were inconsistencies, as well as "digressive" passages, but wrote that "they have not been so great as to reduce the popularity of the work."

Lionel Trilling declared the novel morally bankrupt, and claimed that if it had anything at all to say, it was "this: that moral inertia, the not making of moral decisions, constitutes a very large part of the moral life of humanity." Gerald Walton agreed: "It is not difficult to criticize Ethan Frome," he wrote, citing the bleakness of the setting and the grotesqueness of the characters. He called the end "unrelievedly wretched." Marius Bewley, on the other hand, saw moral choices both in Ethan's plan to ask the Hales for money so he could run away with Mattie, and to die with her rather than to be parted from her. K. R. Shrimvasa Iyengar also saw moral intention in Wharton's message that "to fail in love ... is to set up evil currents." Critic David Eggenschwiler concurred: "Ethan's refusal to cheat Andrew Hale is his last decisive act in the novel."

Critics have praised the use of symbolism and irony in the novel, the development of characters, and the economy of language. Bernard called the use of imagery and symbolism to get around the problem of the characters' inarticulateness "masterful." In what sounds like a backhanded compliment, R. Baird Shuman found the book to be "such a mixture of good and bad writing technique that it is a valuable book to use for discussions of writing." Bernard repeats an early criticism that Ethan lacks a tragic dimension in the Greek sense. "His tragedy is entirely of his own making." But others disagreed. Edwin Bjoerkman argued that Ethan lives "between those two spectres of his lost hopes: the woman he needed and the woman he loved. All other tragedies that I can think of seem mild and bearable beside this one."