Two years before Sylvia Plath published The Bell Jar, her collection of poetry The Colossus opened to some good reviews, particularly in the United States. That Plath published The Colossus under her own name but published The Bell Jar under the pseudonym of Victoria Lucas meant the reviewers would judge the latter on its own merits. Of course, the original critics of The Bell Jar did note that its author was the estranged wife of Ted Hughes, who was becoming a successful poet in his own right.

Some early reviews were encouraging. Robert Taubman, in a New Statesman article, called The Bell Jar "a clever first novel ... The first feminine novel ... in the Salinger mood," referring to J D. Salinger's famous novel Catcher in the Rye and some of his shorter work. Laurence Lerner in The Listener praised the book as "brilliant and moving," while Rupert Butler, in Time and Tide, found the book "terribly likeable" and "astonishingly skillful." All three critiques were published in January 1963, less than a month before Plath's suicide. By 1966, The Bell Jar had been published in England under Plath's real name.

Many latter reviews compared The Bell Jar to Plath's posthumous collection of poetry, Ariel. C. B. Cox in a 1966 review for Critical Quarterly believed "the novel seems a first attempt to express mental states which eventually found a more appropriate form in poetry." However, Robert Scholes, writing for The New York Times Book Review, called The Bell Jar "a fine novel, as bitter and remorseless as her last poems." Like many other critics, he compared The Bell Jar to some of J. D. Salinger's work when he called the former, "the kind of book Salinger's Franny might have written about herself ten years later." (Franny is one of the fictional Glass children who appears in Salinger's Franny and Zooey as well as in some of his short stories.) M. L. Rosenthal wrote in the Spectator of the novel's "magnificent sections whose candour and revealed suffering will haunt anyone's memory."

Since its publication in 1963, The Bell Jar has steadily acquired a reputation as a feminist classic. In 1972, Patricia Meyer Spacks, in her Hudson River review, listed the ways in which the novel concerns female sexuality, "babies in glass jars, women bleeding in childbirth, Esther herself thrown in the mud by a sadist, hemorrhaging after a single sexual experience. To be a woman is to bleed and burn." Fourteen years later, Paula Bennett, in her book My Life a Loaded Gun: Female Creativity and Feminist Politics, perceived the novel as offering a brilliant evocation of "the oppressive atmosphere of the 1950s and the soul-destroying effect this atmosphere could have on ambitious, high-minded young women like Plath."

Although Sylvia Plath and her mother had feared publication of The Bell Jar in the United States would embarrass many of the author's friends and acquaintances, much of the American reaction was mature. Some critics, including Ronald De Feo and Ruth Bauerle, defended the book as more than thinly veiled autobiography. It eventually became a Book-of-the-Month club selection, and Book World considered it one of the "Fifty Notable Books" of 1971.

In light of Plath's own suicide ten years after the time The Bell Jar actually took place, some readers and critics have found the novel's relatively optimistic conclusion to be unconvincing. Others, disagreeing, found it to be psychologically sound. For example, Tony Tanner in City of Words: American Fiction, 1950-1970 believed the novel was "perhaps the most compelling and controlled account of a mental breakdown to have appeared in American fiction."

In retrospect, it must be stressed that Esther's problems in The Bell Jar aren't entirely typical of female teenagers' troubles today. As Susan Sniader Lanser and Teresa De Lauretis have written, Plath's work is about one woman in a specific period of American history when exciting career opportunities for women were rare. Esther's dilemma—marriage and children versus successful career—cannot be so easily generalized today. Also, while many male and female teenagers today face the difficult decision of whether to lose their virginity before marriage, few obsess over it to the point that Esther does in The Bell Jar.