A genre of speculative fiction known as fantasy is one that includes magical aspects, is frequently set in a made-up universe, and occasionally draws inspiration from mythology and folklore. It is also possible to refer to "works of this genre," which are typically literary works, as "fantasy."

Its origins lie in oral traditions, which later gave rise to fantasy writing and theatre. It has further branched out into different mediums since the turn of the 20th century, including film, television, graphic novels, comics, anime, and video games. Xuanhuan (for Chinese fantasy works with a strong emphasis on magic) and qihuan (for Chinese fantasy novels that take place in fantastical realms that integrate aspects from European and Chinese fantasy) are other synonyms for the genre, however they are rarely used. Despite the possibility of having macabre or scientific elements, fantasy differs from science fiction and horror in that they don't. In popular culture, Earth-like surroundings with a sense of otherness are a common theme in fantasy settings.

The majority of fantasy stories have magic or other supernatural elements as a central theme, location, or plot device. In many of these worlds, magic, magic practitioners (such as sorcerers, witches, and so forth), and magical beings are prevalent.

The use of narrative elements by the author that are not dependent on history or the natural world for their coherence is a distinguishing characteristic of fantasy. In contrast to fantasy, realistic fiction does not have to take into account the natural laws and history of reality. The author of fantasy employs worldbuilding to construct settings, people, and circumstances that would not be conceivable in real life.

Although the incorporation of supernatural elements, such as magic, is another defining trait of the fantasy genre, this is not always the case. Many fantasy authors draw inspiration from real-world folklore and mythology.
Due to the fact that science fiction and horror are the two main subgenres of speculative literature, fantasy is frequently contrasted with them. Fantasy differs from science fiction in that the narrative components are more believable. When compared to fantasy stories, science fiction stories are unlikely but can appear to be possible through rational scientific or technical extension.In order to produce effective fantasies, authors must rely on the readers' suspension of disbelief, an acceptance of the absurd or impossible for the sake of fun. Fantasy and horror can be distinguished from one another despite the supernatural playing a significant role in both genres. Fear is primarily evoked in horror by the protagonists' flaws or incapacity to combat the enemies.