The Bell Jar is Sylvia Plath's only novel, which was originally published under the pseudonym Victoria Lucas in 1963. The novel is autobiographical, with the names of places and people changed to avoid causing offense. After Plath's suicide, the novel was published under her real name, and the novel did cause great offense. This resulted in a successful lawsuit by one individual (who is portrayed as "Joan" in the book), where the court ruled that the novel unfairly branded her as homosexual.

The protagonist, Esther Greenwood, gains a scholarship in New York to work at a prominent magazine, at the time of the Rosenbergs' execution. Esther makes friends with Doreen, and although she thinks that Doreen is a "dirty common slag", Esther attempts to be like her in every way, attempting to lose her virginity at every opportunity, which becomes an unhealthy obsession. She also finds a patron in Philomena Guinea, who was based on Plath's own patron, Olive Higgins Prouty, author of Stella Dallas and Now, Voyager. Plath's real-life magazine scholarship was at Mademoiselle magazine, which became defunct in November, 2001. Esther has a boyfriend, Buddy Willard, who is diagnosed with tuberculosis and is sent to a sanatorium. Esther struggles to cope with life in New York and moves back to live with her mother, who she believes was in part responsible for the death of her father, who was a diabetic. Esther becomes increasingly depressed, and finds herself unable to sleep. She sees a psychiatrist who quickly recommends electroshock therapy. Esther makes several attempts at suicide after this, the final and most serious at the end of chapter thirteen. True to Sylvia Plath's actual suicide attempt, Esther leaves a note saying she is taking a long walk, crawls into the cellar, and swallows almost 50 sleeping pills. She survives, and is then sent to a mental hospital, making new friends along the way, and is again subjected to intense electroconvulsive therapy. Esther loses her virginity to Irwin, a professor of mathematics, in chapter nineteen, near the end of the book, and she suffers immense bleeding and is admitted to a hospital.

The book is full of irony, especially in comparison to Plath's life. Esther continually makes reference to her hatred of children and how she would never have any, but Sylvia Plath did in fact have children with the English poet Ted Hughes. There are also connections between Plath's life and the Rosenbergs. Plath was subjected to electric shock therapy, and the Rosenbergs were executed in the electric chair; when she committed suicide, she left her two children behind, as did the Rosenbergs.

Some critics have likened the book to a female version of The Catcher in the Rye by J.D. Salinger.