Shin Megami Tensei III: Nocturne is a role-playing video game developed by Atlus for the PlayStation 2. It was published by Atlus in Japan and North America, and by Ghostlight in Europe. It is the third numbered entry in the Shin Megami Tensei series, the central series in the Megami Tensei franchise. Multiple versions of the game have been published: the original version was published in Japan by Atlus in 2003, while a director's cut was released in 2004 in Japan. The director's cut was localized and released in North America in 2004 as Shin Megami Tensei: Nocturne and in PAL regions in 2005 as Shin Megami Tensei: Lucifer's Call. A high-definition remaster was released for the Nintendo Switch and PlayStation 4 in Japan in 2020, and was internationally released in 2021 on those consoles and Windows.

Atlus Co., Ltd. is a Japanese video game developer, publisher, arcade manufacturer and distribution company based in Tokyo. A subsidiary of Sega, the company is known for video game series such as Megami Tensei, Persona, Etrian Odyssey, and Trauma Center, as well as Print Club (Purikura) arcade machines. Its corporate mascot is Jack Frost, a snowman-like character from their Shin Megami Tensei series. Outside of video games, the company is known for their Purikura arcade machines, which are selfie photo sticker booths popular in East Asia.