Monika is a fictional character and the main antagonist of the visual novel Doki Doki Literature Club! The character was created by Dan Salvato and voiced by Jillian Ashcraft. While Monika initially appears as the main tutor and supporting character that guides the player on their path to romance the three provided love interests, she is later revealed to be self-aware of her existence as a video game character; her words, actions and surroundings become increasingly malicious as she makes her intentions clear.

Being self-aware, she becomes attached to the person behind the avatar of her childhood friend Sayori, which causes her to subsequently change the code so that Sayori hangs herself, Yuri stabs herself, and Natsuki is deleted.