Blue Exorcist (Japanese: 青の祓魔師エクソシスト, Hepburn: Ao no Ekusoshisuto) is a Japanese manga series written and illustrated by Kazue Kato. The story revolves around Rin Okumura, a teenager who discovers that he and his twin brother Yukio are the sons of Satan, born from a human woman, and he is the inheritor of Satan's powers. When Satan kills their guardian, Rin enrolls at True Cross Academy to become an exorcist under Yukio's tutelage in order to defeat Satan. The manga has been serialized in Shueisha's shōnen manga magazine Jump Square since April 2009, with individual chapters collected in 34 tankōbon volumes as of May 2026. Viz Media has licensed the manga for English release in North America, with the first volume released in April 2011.

Blue Exorcist was adapted into an anime television series produced by A-1 Pictures, broadcast from April to October 2011. An anime film, Blue Exorcist: The Movie, premiered in December 2012. A second season, subtitled Kyoto Saga, aired from January to March 2017. A third season produced by Studio VOLN, subtitled Shimane Illuminati Saga, aired from January to March 2024. A fourth season was split in two cours; the first cours, subtitled Beyond the Snow Saga, aired from October to December 2024, while the second cours, subtitled The Blue Night Saga, aired from January to March 2025. The anime series has been licensed in English by Aniplex of America.

By December 2022, Blue Exorcist had over 25 million copies in circulation. The manga has been well received by readers, with sales having received a boost thanks to the anime's release.

The story revolves around Rin Okumura, who, along with his younger twin Yukio Okumura, was raised by Father Shiro Fujimoto, an Exorcist. One day, Rin learns that he and Yukio are the sons of Satan. Witnessing Shiro dying to protect him, Rin draws the demon-slaying sword Kurikara (倶利伽羅), which restrains his demonic powers. From that moment on, Rin not only gains demonic features like fangs and a tail, but also the power to ignite into blue flames that destroy almost anything he touches.

Rin wishes to become an Exorcist like his guardian to become stronger and to defeat Satan. He enrolls at the prestigious True Cross Academy (正十字学園, Sei Jūji Gakuen), an exorcist cram school, which is actually the Japanese branch of the True Cross Order (正十字騎士團, Sei Jūji Kishidan), an international organization dedicated to protect Assiah from Gehenna. Much to his surprise, Rin finds that Yukio is already a veteran Exorcist and is one of his teachers. Thus begins Rin's journey to become an Exorcist, accompanied by his brother and his fellow students who quickly become his close friends.