A femme fatale (pronounced /ˌfɛm fəˈtæl/ or /ˌfɛm fəˈtɑːl/; French: [fam faˈtal], with all [a]'s) is a mysterious and seductive woman[1] whose charms ensnare her lovers in bonds of irresistible desire, often leading them into compromising, dangerous, and deadly situations. She is an archetype or stock character of literature and art. Her ability to entrance and hypnotize her victim was in the earliest stories seen as being literally supernatural, hence the most prosaic femme fatale today is still described as having a power akin to an enchantress, vampire, female monster or demon.

The phrase is French for "deadly woman". A femme fatale tries to achieve her hidden purpose by using feminine wiles such as beauty, charm, and sexual allure. Typically, she is exceptionally well-endowed in addition to possessing these qualities. In some situations, she uses lying or coercion rather than charm. She may also be (or imply to be) a victim, caught in a situation from which she cannot escape; The Lady from Shanghai (a 1947 film noir) is one such example.

Although typically villainous, femmes fatales have also appeared as antiheroines in some stories, and some even repent and become heroines by the end of the tale. In social life, the femme fatale tortures her lover in an asymmetrical relationship, denying confirmation of her affection. She usually drives him to the point of obsession and exhaustion so that he is incapable of making rational decisions.