Lilith ( LIH-lith; Hebrew: לִילִית, romanized: Līlīṯ), also spelt Lilit, Lilitu, or Lilis, is a female figure in Mesopotamian and Judaic mythology, theorized to be the first wife of Adam and supposedly the primordial she-demon. Lilith is cited as having been "banished" from the Garden of Eden for not complying with and obeying Adam. She is thought to be mentioned in Biblical Hebrew in the Book of Isaiah, and in Late Antiquity in Mandaean mythology and Jewish mythology sources from 500 CE onward. Lilith appears in historiolas (incantations incorporating a short mythic story) in various concepts and localities that give partial descriptions of her. She is mentioned in the Babylonian Talmud (Eruvin 100b, Niddah 24b, Shabbat 151b, Baba Bathra 73a), in the Book of Adam and Eve as Adam's first wife, and in the Zohar Leviticus 19a as "a hot fiery female who first cohabited with man". Many traditional rabbinic authorities, including Maimonides and Menachem Meiri, reject the existence of Lilith.

The name Lilith stems from lilû, lilîtu, and (w)ardat lilî). The Akkadian word lilu is related to the Hebrew word lilith in Isaiah 34:14, which is thought to be a night bird by some modern scholars such as Judit M. Blair. In the Ancient Mesopotamian religion, found in cuneiform texts of Sumer, Assyria, and Babylonia Lilith signifies a spirit or demon.

Lilith continues to serve as source material in today's popular culture, Western culture, literature, occultism, fantasy, and horror.