Dusk Maiden of Amnesia (Japanese: 黄昏乙女×アムネジア, Hepburn: Tasogare Otome × Amunejia), stylized as Dusk maiden of Amnesia, is a Japanese manga series written and illustrated by the duo Maybe . It was published by Square Enix and serialized in the Monthly Gangan Joker magazine from April 2009 to June 2013, with its chapters collected in ten tankōbon volumes. An anime television series adaptation by Silver Link aired between April and June 2012. The anime series has been licensed by Sentai Filmworks in North America.

Teiichi Niiya, a first-year student at Seikyou Private Academy, befriends Yuuko Kanoe, a ghost with fragmented memories. Though he initially assists her without much focus on the school's supernatural legends, their dynamic shifts as he grows closer to his classmates Kirie and Okonogi. Unaware of her own emotional limitations, Yuuko suppresses her jealousy, unknowingly transferring those feelings—along with the lingering resentment from her past—into "Shadow Yuuko", a darker manifestation of herself.

As Teiichi helps Yuuko recover her memories, the truth of her death unfolds. A key figure from her past emerges: a melancholic girl named Asa-chan, whose family perished in the plague that ravaged their town. Initially distant, Asa feared infecting Yuuko but gradually warmed to her kindness. When the superstitious townspeople sought a sacrifice to appease the gods, they forced Asa into the role of Akahito-sama, a divine messenger tasked with selecting a victim. Yuuko, believing Asa was in danger, rushed to the shrine, only for the villagers to misinterpret Asa's fearful cry as a divine decree. In the ensuing chaos, Yuuko was thrown down the shrine's steps, sustaining fatal injuries. Contrary to initial assumptions, Yuuko's sister had no hand in her death—in fact, she had previously rejected Yuuko's self-sacrificial notions.

Teiichi uncovers this truth before Yuuko does, inadvertently causing her to lose awareness of him. To restore their connection, he confronts Shadow Yuuko, reconciling her with Yuuko's true self. He reveals that Asa survived and later became his grandmother, meaning Yuuko's sacrifice ultimately led to their meeting. With her regrets resolved, Yuuko begins fading from existence. In their final moments together, she shares a bittersweet day with Teiichi, culminating in a tearful kiss. Though Kirie lightly teases him afterward, she understands Yuuko's irreplaceable role in his heart.

Unknown to them, the kiss instills a new regret within Yuuko—her desire to remain with Teiichi. This emotion anchors her to him, ensuring she does not pass on. Instead, she becomes bound to Teiichi eternally, her existence now tied not to the school but to the boy who refused to let her go.