The film is loosely based on the first and second stories of day three of ten of The Decameron, a collection of novellas by Giovanni Boccaccio, a 14th-century Italian writer.

It stars an ensemble cast featuring Alison Brie, Dave Franco, Kate Micucci, Aubrey Plaza, John C. Reilly, and Molly Shannon.

The plot jointly follows the lives of three nuns at a convent in the countryside who try to fornicate with a young gardener posing as a deaf-mute after he escapes from being punished by his lord for adultery with the man's wife.

The three nuns at the center of the story are: Alessandra, who wants to marry her suitor but is held at the convent due to her father's support of the church; Ginevra, a gossip; and Fernanda, a violent sadist.

Fernanda's friend Marta appears and encourages Alessandra and Ginevra to get drunk with the sacramental wine while explaining how being with a man is the greatest possible pleasure.

Massetto is returned to his master and is held in a jail cell with the impending threat of torture and death until the three nuns (who have reconciled and formed an even stronger friendship) help him escape.

Jeff Baena came up with the idea for The Little Hours after having a discussion while high and watching DOGTV with a filmmaker friend, Joe Swanberg, during which Baena explained his college studies of sexual transgression in the Middle Ages and Giovanni Boccaccio's The Decameron, and his long-standing desire to make a "medieval combat nun movie".

[3][4] While visiting potential locations, Baena did not explain that the film was an adaptation of The Decameron, due to it remaining controversial in Catholic areas of Italy.

In adapting the medieval work, he aimed to "achieve the spirit of the original story" through keeping its sense of humor and reflecting the social and political dynamics utilized by Boccaccio.

[10] In April 2016, it was announced that the film would star Alison Brie, Dave Franco, Kate Micucci, Plaza, John C. Reilly, Molly Shannon, Fred Armisen, Jon Gabrus, Jemima Kirke, Nick Offerman, Adam Pally, Paul Reiser, Lauren Weedman, and Paul Weitz.

[16] Baena looked for a cinematographer through personal recommendations instead of agencies, and chose Quyen Tran, who had worked on the original short film of SMILF with mutual friend Frankie Shaw.

Many such paintings "have very wide, stacked shots with a lot of action happening in one frame", something Tran aimed to emulate for aesthetics and to capture as much of the actors' improvised performances while shooting single-camera.

The Amira is similar to an ENG camera, which Tran found to be of benefit in terms of the ease of using it handheld, as she had to operate all equipment by herself.

Another reason to use candles for interior day shots was Tran's motivation to aim for realistic period lighting and thus a lack of other backlighting (to separate actors from backgrounds) unless there were windows.

[29] Prior to its theatrical release, various Catholic groups protested the film's distribution: America Needs Fatima started an online petition in June 2017 that gained 31,000 signatories, sending a letter to Gunpowder & Sky to complain about the film for "wrongly" representing priests and nuns being immoral; a campaign of the American Society for the Defense of Tradition, Family and Property had an online petition gain 20,000 signatures and requested Gunpowder & Sky cancel the release of the film; and the Catholic League wrote a disparaging article about Sundance for premiering both The Little Hours and Novitiate.

IndieWire noted in its coverage of the protests that the content being complained about was present in the 14th century source material, and that The Little Hours was primarily a raunchy comedy and so "it's hard to view the film as any kind of attack on Catholicism or religion.

"[6] Baena responded to the complaints by saying that many nuns of the Middle Ages were not pious – but instead effectively trapped in convents – and had the same emotional complexity and desires as modern people, as well as reflecting that "the whole point of the church" is to recognize human flaws.

The website's critical consensus reads: "The Little Hours gets plenty of goofy mileage out of its gifted ensemble, anchoring its ribald laughs in a period comedy with some surprisingly timely subtext.