These are all the backgrounds used in Doki Doki Literature Club!.
The Classroom appears in Acts 1, 2, and 4. It is meant to depict any classroom that is not the Literature Club. Examples of this are the protagonist’s classroom and The Classroom where Sayori’s second CG takes place.
The hallway near the Literature Club appears in Acts 1, 2, and 4. The hallway is part of the third-year wing but also holds the Literature Club.
This picture represents the exterior of Sayori’s and the protagonist's house. It appears only in Act 1.
This picture is of the protagonist’s kitchen. It is only seen on Natuski’s route in Act 1 on Day 4. Natsuki’s third CG is obtained here.
This picture is of the protagonist’s bedroom. It is only seen on Yuri’s route in Act 1 on Day 4. Yuri’s third CG is obtained here.
This notebook is the background for the poem game that happens in Acts 1 and 2. On the left page, chibi versions of Sayori (Act 1 only), Natsuki and Yuri can be found. On the right page, the player has to click 20 different words to appeal to the girls. Monika may jump from the off-screen bottom when a word is selected during Act 2.
This glitched version of the notebook is used for Act 3's poem game when Monika asks you to write a poem for her. In this version of the poem game, the only girl that appears on the left is Monika, and the words on the right page are all normal or glitchy variations of her name.
This is the version of the classroom used in Act 3 during Monika's discussion with the player. Outside of the windows, a space-like animation plays constantly, so it's well known as the "space classroom." Sometimes, a flare lights the room briefly from outside.
This glitched version of the space classroom is used at the end of Act 3 when the player deletes Monika. It is also used in Act 4 during the bad ending. It's where Sayori takes the player after confessing that she has knowledge of all the past events.
This is Sayori's bedroom, and it's used only in Act 1. A 2017 calendar can be seen on the left. It appears to be messy, like how the protagonist describes it during one of his discussions in the Literature Club.
This version of Sayori's bedroom is seen in Act 1 during her suicide scene. In that scene, the background constantly shifts between this and the normal version, likely as the result of Monika’s modifications breaking the script of the game.
This is the residential area seen in Acts 1, 2 and 4. It represents a certain area between the protagonist's house and The School. A few houses and bushes can be seen along with what appears to be a bus stop.