In Arabian mythology, a genie or djinn is a type of spirit, similar to the Western concept of a ghost. In Pre-Islamic thought, a genie had magical powers and was sometimes, though not always, wicked, or at least mischievous. In Islam, the genie has become more analogous to a demon, with the Devil as the most powerful of the genies, while in Western culture, the genie is typically portrayed as a magical spirit with no religious connotations who is capable of granting wishes. The English word genie comes from the French for "spirit," which was used to translate djinn in the first French translations of the Arabian Nights.

The Western concept of the genie is drawn mainly from the tale of Aladdin in the Arabian Nights, in which Aladdin frees a genie from his imprisonment in a lamp and is granted wishes in return. However, a wider reading of the Arabian Nights reveals the genie as a creature quite different from the modern Western version. There are different types of genies with different sets of magical powers. In some mythology, genies are categorized by the element - fire, water, earth, or air - that governs them. Some types of genies are frightening, such as the ghul, which lends its name to the Modern English ghoul, and the succubus-like female genies.

In Islam, genies are believed to live among humans but to be invisible for the most part. Genies are said to have free will, like humans but unlike angels, and to have the capacity for good or evil. There are references to genies throughout the Qur'an, and the Devil, called Shaitan in Islam, is the most powerful. Evil genies are similar to demons in Christian thought and can possess people physically or tempt them into sin.

Though the genie in Western culture is usually benign, it is often mischievous and sometimes borders on the more frightening versions from the Middle East. Dangerous genies in the West often work by distorting the wishes of those they are supposed to serve or by taking their words very literally. This trope in Western folklore predates the arrival of the genie in Western consciousness and is summarized in the adage, "Be careful what you wish for."