Samois was a lesbian-feminist BDSM organization based in San Francisco that existed from 1978 to 1983. It was the first lesbian S/M group in the United States. It took its name from the fictional estate of Anne-Marie, a lesbian dominatrix character in Story of O, who pierces and brands O. Well-known members of the group included the writer Pat Califia and feminist academic Gayle Rubin.

The roots of Samois were in a group called Cardea, a women’s discussion group within the mixed-gender S/M group, the Society of Janus. Cardea existed only briefly, from 1977 to 1978 before discontinuing, but a core of lesbian members, including Califia and Rubin, were inspired to start Samois, an exclusively lesbian BDSM group.

Samois was strongly rebuked (and sometimes picketed) by Women Against Violence in Pornography and Media (WAVPM), an early anti-pornography feminist group. WAVPM, like later anti-pornography feminists, was very strongly opposed to sadomasochism, seeing it as ritualized violence against women. Samois members felt strongly that their way of practicing SM was entirely compatible with feminism, and held that the kind of feminist sexuality advocated by WAVPM was conservative and puritanical. Samois openly confronted WAVPM with their position, and the exchanges between the two groups were among the earliest battles of what later became known as the Feminist Sex Wars, with Samois being among the very earliest advocates of what came to be known as sex-positive feminism. The book Coming to Power, edited by members of the Samois group and published in 1981, was a seminal work of the lesbian BDSM movement.

Samois split up in 1983 amid personal infighting; however, in 1984 Gayle Rubin went on to form another organization called The Outcasts. The Outcasts lasted until 1997, until they too split due to infighting. A breakaway group, The Exiles, is still extant as of 2012 and carries on in the tradition of Samois and The Outcasts. In 1996, Pat Califia and Robin Sweeny published an anthology titled The Second Coming: A Leatherdyke Reader that also contained historical information on The Outcasts, as well as other lesbian BDSM groups such as the Lesbian Sex Mafia and Briar Rose.