A dominatrix (/ˌdɒmɪˈneɪtrɪks/ ^ⓘ DOM-in-AY-triks; pl. dominatrixes or dominatrices /ˌdɒmɪˈneɪtrɪsiːz, ˌdɒmɪnəˈtraɪsiːz/ DOM-in-AY-triss-eez, DOM-in-ə-TRY-seez), or domme, is a woman who takes the dominant role in BDSM activities. The BDSM practice is called female dominance, or femdom. A dominatrix can be of any sexual orientation, but this does not necessarily limit the genders of her submissive partners. Dominatrices are popularly known for inflicting physical pain on their submissive subjects, but this is not done in every case. In some instances erotic humiliation is used, such as verbal humiliation or the assignment of humiliating tasks. Dominatrices also make use of other forms of servitude. Practices of domination common to many BDSM and other various sexual relationships are also prevalent. A dominatrix is typically a paid professional (pro-domme) as the term dominatrix is little-used within the non-professional BDSM scene.

Dominatrix is the feminine form of the Latin dominator, a ruler or lord, and was originally used in a non-sexual sense. Its use in English dates back to at least 1561. Its earliest recorded use in the prevalent modern sense, as a female dominant in sadomasochism, dates to 1961. It was initially coined to describe a woman who provides punishment-for-pay as one of the case studies within Bruce Roger's pulp paperback The Bizarre Lovemakers. The term was taken up shortly after by the Myron Kosloff title Dominatrix (with art by Eric Stanton) in 1968, and entered more popular mainstream knowledge following the 1976 film Dominatrix Without Mercy.

The term domme is likely a coined pseudo-French feminine inflection of the slang dom (short for dominant). The use of domme, dominatrix, dom, or dominant by any woman in a dominant role is chosen mostly by personal preference and the conventions of the local BDSM scene. The term mistress or dominant mistress is sometimes also used. Female dominance (also known as female domination or femdom) is a BDSM activity in which the dominant partner is female. However, while the term mistress is often used in the media and by paid professional dominatrices and their submissives, members of the BDSM community often avoid it. This is because it can be confused with mistress in the sense of a woman who has an illicit relationship with a married man, a term which has the negative implication of cheating on a partner. Since there is a large overlap between the BDSM and polyamory communities, where ethical conduct is a prime concern, any such relationship is a source of disapproval.

Although the term dominatrix was not used, the classic example in literature of the female dominant-male submissive relationship is portrayed in the 1870 novella Venus in Furs by Austrian writer Leopold von Sacher-Masoch. The term masochism was later derived from the author's name by Richard von Krafft-Ebing in the latter's 1886 forensic study Psychopathia Sexualis.

The history of the dominatrix is argued to date back to rituals of the goddess Inanna (or Ishtar as she was known in Akkadian), in ancient Mesopotamia. Ancient cuneiform texts consisting of "Hymns to Inanna" have been cited as examples of the archetype of the powerful, sexual female displaying dominating behaviors and forcing gods and men into submission to her. The pseudonymous archaeologist and BDSM historian Anne O. Nomis notes that Inanna's rituals included cross-dressing of cult personnel, and rituals "imbued with pain and ecstasy, bringing about initiation and journeys of altered consciousness; punishment, moaning, ecstasy, lament and song, participants exhausting themselves with weeping and grief."

The fictional tale of Phyllis and Aristotle, which became popular and gained numerous versions from the 12th century onwards, tells the story of a dominant woman who seduced and dominated the male intellect of the greatest philosopher. In the story, Phyllis forces Aristotle to kneel on the ground so that she rides on his back while whipping and verbally humiliating him.

The profession appears to have originated as a specialization within brothels, before becoming its own unique craft. As far back as the 1590s, flagellation within an erotic setting is recorded. The profession features in erotic prints of the era, such as the British Museum mezzotint "The Cully Flaug'd" (c. 1674–1702), and in accounts of forbidden books which record the flogging schools and the activities practised.

Within the 18th century, female "Birch Disciplinarians" advertised their services in a book masked as a collection of lectures or theatrical plays, entitled "Fashionable Lectures" (c. 1761). This included the names of 57 women, some actresses and courtesans, who catered to birch discipline fantasies, keeping a room with rods and cat o' nine tails, and charging their clients a Guinea for a "lecture".