A magical girlfriend, exotic girlfriend, monster girlfriend, nonhuman woman, or supernatural lover, is a female stock character often associated with romantic comedy anime and manga series, and is sometimes considered a genre of its own, or as the leading lady of the "fantastic romance" genre, which combines the fantasy and romance genres.

As Thomas Lamarre states, "Anime fans become familiar with a whole range of female figures that are either not really human (robots, aliens, deities, animals), or that possess extra-human powers of some kind or another (from cyborg enhancements to magical or psychic abilities), which take them beyond the merely human woman."

Magical girlfriends can be one or many in a single series (always attached to the male lead). Because of the tendency for rivals to appear even when there is one female lead and because of the unnatural gender balance among the cast, magical girlfriend comedies are often conflated with harem comedies. A good example of this conflation is Oh My Goddess! which is "one of the prototypical 'harem' titles" despite the short-lived nature of most of the romantic rivalries.

Magical girlfriends initially derived from the US television series Bewitched and I Dream of Jeannie, which were dubbed for the Japanese market. Sally the Witch was the first anime series inspired by Bewitched, leading to the popularity of magical girls in Japanese anime.

Often series in the genre start with the male lead encountering the female lead either by pure chance or by an unusual event, after which the female lead somehow becomes bound or otherwise dependent upon him, often forcing a situation of cohabitation. In many cases, this situation is repeated with other characters (Tenchi Muyo!), overlapping with the harem genre. However, the male lead is often inexperienced with women despite typically being a "nice guy". This situation often prevents the relationship from advancing beyond a platonic level throughout most of the series, as an ideal girlfriend doesn't come on strong herself and is generally passive in the relationship.

In parodies, the character may be "too young" (i.e. Nakahito Kagura in Steel Angel Kurumi; Negi Springfield in Negima! Magister Negi Magi) or otherwise have a more rational, ambivalent attitude towards women. A famous early reversal of the cliche occurs with the overtly lecherous Ataru Moroboshi of Urusei Yatsura, who is simply uninterested in monogamous relationships despite the fact few women besides his romantically aggressive alien girlfriend find him attractive.

Another feature is that soon after the male and female leads begin to live together, other (usually female) characters from the female (or male) lead's origin appear (friends, siblings, relatives, rivals or even enemies), either becoming frequent visitors, cohabitors, or generally causing a disruption, or even moving in with the lead couple. Sometimes a character from the male lead's origin will appear. Examples include Ai Yori Aoshi, where Kaoru's half-brother tries to take Aoi for himself, and Omamori Himari, where demonslayer Kuesu Jinguuji appears in volume 3 to claim Yuuto Amakawa as her betrothed.

Even when there is one female lead, various rivals always threaten the relationship between the lead characters, often creating complicated "love polygons". These can vary from being from mundane characters such as men who fight for the affection of the female (and rarely male) lead, or rivals from the female lead's origins.