Jinn (Arabic: جِنّ‎), also romanized as djinn or anglicized as genies, are supernatural beings in pre-Islamic Arabian religion and Islam. Like humans, they are accountable for their deeds and can be either believers (Mu'minun) or unbelievers (kuffar), depending on whether they accept God's guidance.

Since jinn are neither innately evil nor innately good, Islam acknowledged spirits from other religions and could adapt them during its expansion. Likewise, jinn are not a strictly Islamic concept; they may represent several pagan beliefs integrated into Islam. Islam places jinn and humans on the same plane in relation to God, with both being subject to divine judgement and an afterlife. The Quran condemns the pre-Islamic Arabian practice of worshipping or seeking protection from them.

While they are naturally invisible, jinn are supposed to be composed of thin and subtle bodies (أَجْسَام, ajsām) and are capable of shapeshifting, usually choosing to appear as snakes, but also as scorpions, lizards, or humans. A jinn's interaction with a human may be negative, positive, or neutral; and can range from casual to highly intimate, even involving sexual activity and the production of hybrid offspring. However, they rarely meddle in human affairs, preferring instead to live among their own in a societal arrangement similar to that of the Arabian tribes. Upon being disturbed or harmed by humans, they usually retaliate in kind, with the most drastic interactions leading them to possess the assailant's body, thus requiring exorcism.

Individual jinn appear on charms and talismans. They are called upon for protection or magical aid, often under the leadership of a king. Many people who believe in jinn wear amulets to protect themselves against their assaults, as they may be called upon by sorcerers and witches to cause harm. A commonly held belief is that jinn cannot hurt someone who wears something with the name of God (الله, Allāh) written on it. These folkloric beliefs and practices, although especially common throughout the Muslim world in the past, have been met with increasing disapproval due to their association with idolatry.

Jinn is an Arabic collective noun deriving from the Semitic root JNN (Arabic: جَنّ / جُنّ, jann), whose primary meaning is 'to hide' or 'to adapt'. Some authors interpret the word to mean, literally, 'beings that are concealed from the senses'. Cognates include the Arabic majnūn (مَجْنُون, 'possessed' or, generally, 'insane'), jannah (جَنَّة, 'garden', 'eden' or 'heaven'), and janīn (جَنِين, 'embryo'). Jinn is properly treated as a plural (however in Classical Arabic, may also appear as jānn, جَانّ), with the singular being jinnī (جِنِّيّ), which the English word "genie" is derived from.

The origin of the word jinn remains uncertain. Some scholars relate the Arabic term jinn to the Latin genius – a guardian spirit of people and places in Roman religion – as a result of syncretism during the reign of the Roman empire under Tiberius and Augustus; however, this derivation is also disputed. Supporters argue that both Roman genii as well as Arabian jinn are considered to be lesser deities inhabiting local sanctuaries, trees or springs, and persons or families. Aramaic ginnaya (Classical Syriac: ܓܢܝܐ) with the meaning of 'tutelary deity' or 'guardian' are attributed to similar functions and are another possible origin of the term jinn.

Another suggestion holds that the word is of Persian origin and appeared in the form of the Avestic Jaini, a wicked (female) spirit. Jaini were among various creatures in the possibly even pre-Zoroastrian mythology of peoples of Iran. Wensick advocates a purely Arabic origin of the term, asserting that according to the common Semitic view psychic and bodily affections are caused by spirits. An object reacting upon such an affect would be an incarnation of said spirit. Since these spirits are covered from the sight of humans, they would have been called jinn.

The anglicized form genie is a borrowing of the French génie, also from the Latin genius. It first appeared in 18th century translations of the Thousand and One Nights from the 1706 French edition, where it had been used owing to its rough similarity in sound and sense and further applies to benevolent intermediary spirits, in contrast to the malevolent spirits called 'demon' and mostly-benevolent 'heavenly angels', in literature. In Assyrian art, the modern term used for creatures ontologically between humans and divinities is also genie.