Oh! My Goddess (original name Aa! Megami-sama, sometimes called Ah! My Goddess, 「ああっ女神さまっ」) is a manga and anime series by Kosuke Fujishima. The manga began in 1988 as an unintentional spinoff from You're Under Arrest. It proved to be popular, and a five episode OVA series began in 1991, produced by AIC. A superdeformed TV series, Adventures of Mini-Goddess, began in 1998, produced as part of the omnibus show Anime Complex on WOWOW. A movie was produced in 2001.

The story centers around Keiichi Morisato, a hapless college student who loves cars. One day, Keiichi accidentally dials a "goddess hotline" — in the OVAs, he was trying to order noodles; in the manga, he was delivering a message — and the beautiful goddess Belldandy appears before him, offering him one wish. Assuming this is a joke, Keiichi wishes that Belldandy (whom he finds very attractive) would stay with him forever, and his wish is immediately granted. This is complicated by the fact that Belldandy's two sisters, Urd and Skuld, move in as well, and bring a whole lot of trouble with them.

The series is well-loved by fans for several reasons: its artwork is generally recognized as beautiful, and the storylines balance screwball comedy with sweet romance that never gets saccharine.

Bits of Norse mythology are incorporated in the comic. The three goddesses are based on the Norns (analogous to the Greek fates) Urd, Verdandi/Verthandi, and Skuld, who represent the past, present and future respectively. The goddesses access a computer system called Yggdrasil, which in Norse mythology is the tree that holds up the world. The theme is to add dramatic color and is not strictly held to.

The original Japanese title is "Aa, Megami-sama," the translation of which led to a great deal of debate and flamewars amongst English-speaking anime fans of the early 1990s. The US-anime import company Animeigo obtained the OVA rights and entitled them "Oh! My Goddess." But many felt the title should properly be "Ah! My Goddess." Ultimately Fujishima himself was consulted. His first reaction was side with the "Ah" camp, but once the term "Oh my God" was explained to him, he decided the "Oh" was more appropriate. Pioneer ultimately had the last laugh though, as they chose to use "Ah" in their North American release of the movie (possibly due to Animeigo holding copyright to the "Oh My Goddess" title).