Overview

A threesome is sexual activity that involves three people. It is sometimes called troilism or a ménage à trois. Threesomes can be a one-time encounter or part of an ongoing arrangement, and they occur between people of any combination of sexes and genders. For basic background on human sexual behavior and related topics, see sexuality.

Forms and common arrangements

Arrangements vary widely according to the participants' preferences and identities. Typical configurations include two people who are partners inviting a third person, three single people, or three people in a polyamorous relationship. Sexual activity itself may be simultaneous or sequential and can emphasize interaction among all three participants or focus on pairs within the group.

  • Partner-plus-third: a couple plus a single person.
  • Triad: three people in a committed relationship with each other.
  • Casual triple encounter: three consenting individuals without ongoing commitment.

History and cultural context

References to sexual activity involving three people appear in literature, art, and social practices throughout history. Cultural attitudes vary: some societies and subcultures accept or even celebrate such activity, while others view it as taboo. Public discussion of threesomes has increased with changing norms around sexuality and the visibility of non-monogamous relationships.

Clear, enthusiastic consent from all participants is essential. Before any activity, people should discuss boundaries, safe words, contraception, and sexually transmitted infection (STI) prevention. Safer-sex measures—such as barrier methods, recent testing, and honest disclosure of risks—help reduce health risks. Aftercare and open communication following the encounter support emotional wellbeing.

Legality depends on local laws: consensual adult sexual activity is generally a private matter, but public sex, prostitution, or other regulated behaviors may be illegal in some jurisdictions. Social consequences can include stigma or privacy concerns, so many people consider confidentiality and mutual respect important when deciding whether to participate.

Distinctions and notable facts

Threesomes are a subset of group sex but are distinct from larger gatherings. They can be motivated by curiosity, relationship exploration, or sexual preference. Like any sexual practice, the focus on consent, safety and clear communication determines whether the experience is healthy and positive for everyone involved.