An angry student, Mary Tilford, runs away from the school and, to avoid being sent back, tells her grandmother that the two headmistresses are having a lesbian affair.

Two women, Karen Wright and Martha Dobie, have worked hard to build a girls' boarding school in a refurbished farmhouse.

Mary plans to ask her indulgent grandmother, Amelia Tilford – who also helped Karen and Martha in setting up the school and enrolling pupils – to allow her not to return.

With the help of several well-crafted lies and a book that the girls have been reading in secret, Mary convinces her grandmother that Karen and Martha are having a lesbian affair.

Karen explains to her that it is too late: Mary's lies, together with the community's willingness to believe and spread malicious gossip, have destroyed three innocent lives.

Believing that she would do better to find a subject based in fact,[2] Dashiell Hammett suggested the idea for the play to Hellman after he read a book titled Bad Companions (1930),[3] a true-crime anthology by William Roughead.

[5] Produced and directed by Herman Shumlin, The Children's Hour opened November 20, 1934, at the Maxine Elliott Theatre in New York City.

In December 1935, authorities in Boston declared that the play did not meet the standards of the Watch and Ward Society and that it could not be performed there the following month as scheduled.

Shumlin filed a $250,000 suit for damages, but in February 1936 a Federal judge refused to prevent the city from interfering in the presentation of the play.

[8]: 50 [12] Les Innocentes, André Bernheim's French-language translation of The Children's Hour, was first presented April 21, 1936, at the Théâtre des Arts in Paris.

[15] Philip M. Armato, an assistant professor of Northern Illinois University, argued that while members of the public perceived Karen and Martha as overall good characters, he felt they overlooked the two treating Mary Tilford and Lily Mortar without mercy, before the spreading of the rumors.

Accused of rejecting Hellman's play because of its controversial subject—one of the Pulitzer judges had refused to see it—the selection committee replied that The Children's Hour was not eligible for the award because it was based on a court case and was therefore not an original drama.

[8]: 50 Hellman's play was inspired by the 1810 true story of two Scottish school teachers, Miss Marianne Woods and Miss Jane Pirie, whose lives were destroyed when one of their students accused them of engaging in a sexual relationship, but in the Scottish case, they eventually won their suit, although that did not change the devastation wrought on their lives.

[21] At the time of the play's premiere (1934) the mention of homosexuality on stage was illegal in New York State, but authorities chose to overlook its subject matter when the Broadway production was acclaimed by the critics.

[22] Lillian Hellman directed a Broadway revival of The Children's Hour, produced by Kermit Bloomgarden and presented December 18, 1952 – May 30, 1953, at the Coronet Theatre.

[25] A revival starring Keira Knightley and Elisabeth Moss, directed by Ian Rickson, was presented at London's Harold Pinter Theatre January 22 – May 7, 2011.

However, because of the Production Code, the story was adapted into a heterosexual love triangle, the controversial name of the play was changed, and the movie was eventually released as These Three.

In 1961, the play was adapted, with its lesbian theme intact, for the film The Children's Hour, also directed by Wyler and starring Audrey Hepburn, Shirley MacLaine, and James Garner.

In 1971, the play was produced for the radio by the BBC in its Saturday Night Theatre series starring Jill Bennett and Prunella Scales.