Megami Tensei is a series of role-playing video games (RPGs) mainly made by Atlus. It began with the 1987 game Digital Devil Story: Megami Tensei, which was based on a novel by Aya Nishitani. This series has led to a sequel and other sub-series, such as the Persona and Devil Summoner series. The original Digital Devil Story: Megami Tensei games and the Shin Megami Tensei sub-series are the main part of the series, while other games are considered side stories.

Early games in the series were rarely released outside Japan. The first game released in North America was Jack Bros in 1995, and the first Megami Tensei RPG released there was Revelations: Persona in 1996. The first game released in the PAL region was Shin Megami Tensei: Nocturne in 2003, which came out there in 2005. The series often includes themes like summoning demons, Japanese folklore, and the occult. Even though the series is rooted in Japanese culture and mythology, it has gained a small but dedicated group of fans worldwide. It is Atlus's most important RPG series and one of the largest in Japan. Other media, such as anime and manga, have also been created based on the series.