Originally published under the pseudonym "Victoria Lucas" in 1963, the novel is supposedly semi-autobiographical with the names of places and people changed.

The book is often regarded as a roman à clef because the protagonist's descent into mental illness parallels Plath's experiences with what may have been clinical depression or bipolar II disorder.

[3] In 1953, Esther Greenwood, a 19-year-old undergraduate student from the suburbs of Boston, is awarded a summer internship at the fictional Ladies' Day magazine in New York City.

During the internship, Esther feels neither stimulated nor excited by the work, fashion, and big-city lifestyle that her peers in the program seem to adore.

Esther appreciates the witty sarcasm and adventurousness of Doreen, another intern, but she identifies with the piety of Betsy, an old-fashioned and naïve young woman.

Shortly before the internship ends, she attends a country club party with Doreen, and she is set up with a wealthy Peruvian man named Marco who treats her roughly.

She has been hoping for another scholarly opportunity once she is back in Massachusetts, a writing course taught by a world-famous author, but on her return, she immediately is told by her mother that she was not accepted for the course and finds her plans derailed.

All of her identity has been centered upon doing well academically; she is unsure of what to make of her life once she leaves school, and none of the choices presented to her (motherhood, as exemplified by the prolific child-bearer Dodo Conway, Esther's neighbor, or stereotypical female careers such as stenography) appeal to her.

Esther writes a note for her mother that she "will go out on a long walk", crawls into a well-hidden hole in the cellar, and swallows many sleeping pills that had been prescribed for her insomnia.

She is sent to several different mental hospitals until Philomena Guinea, her college benefactor, supports her stay at an elite treatment center where she meets Dr. Nolan, a female therapist.

Along with regular psychotherapy sessions, Esther is given huge amounts of insulin to produce a "reaction" (a common – and now disproven – psychiatric treatment at the time) and again receives ECT.

Eventually, Esther describes the ECT as beneficial in that it has a sort of antidepressant effect; it lifts the metaphorical bell jar in which she has felt trapped and stifled.

[7] After she separated from Hughes, Plath moved to a smaller flat in London, "giving her time and place to work uninterruptedly.

[8] Upon publication in the United States on 14 April 1971 it became a runaway success, and featured in The New York Times Best Sellers List for many consecutive weeks.

A major plot point in the later chapters is Esther being provided a contraceptive implant by a doctor, which allows her to lose her virginity without fear of falling pregnant and thus being expected become a parent before her time.

A chapter of the novel discusses Esther's plan to "have an affair" with someone, simply to "get it over with" (that is, to lose her virginity), but she is too fearful of the impact of pregnancy.

A good portion of this part of the novel closely resembles the experiences chronicled by Mary Jane Ward in her autobiographical novel The Snake Pit; Plath later stated that she had seen reviews of The Snake Pit and believed the public wanted to see "mental health stuff", so she deliberately based details of Esther's hospitalization on the procedures and methods outlined in Ward's book.

The woman claimed that Plath had put so many details of the students' lives into The Bell Jar that "they could never look at each other again", and that it had caused the breakup of her marriage and possibly others.

[27] Ted Hughes, Plath's husband, suggested that The Bell Jar might have been written as a response to many years of electroshock treatment and the scars it left.

[8][29] Mason Harris of the West Coast Review complimented the novel as using "the 'distorted lens' of madness [to give] an authentic vision of a period which exalted the most oppressive ideal of reason and stability.

"[8] Howard Moss of The New Yorker gave a mixed review, praising the "black comedy" of the novel, but added that there was "something girlish in its manner [that] betrays the hand of the amateur novelist".

"[3] Larry Peerce's The Bell Jar (1979) starred Marilyn Hassett as Esther Greenwood, and featured the tagline: "Sometimes just being a woman is an act of courage."

In July 2016, it was announced that Kirsten Dunst would be making her directorial debut with an adaptation of The Bell Jar starring Dakota Fanning as Esther Greenwood.