->''As [maternal grandmother] was in early clan marriage (Stone Gang) and shared six husbands with another woman, identity of maternal grandfather open to question. But was often so, and I'm content with the grandpappy she picked.''
-->--'''Manual Garcia O'Kelly-Davis''', ''Literature/TheMoonIsAHarshMistress'' by Creator/RobertAHeinlein

People of strange, exotic cultures are often depicted as being far more open to extended marriages, with three or more participants, than we are. Common in SpeculativeFiction, this helps emphasize just how different these people are from us, especially if they are human or HumanoidAliens that resemble us.

In most of the world today, marriage is limited to two people at a time, but that has not always been the case, there are a few places where it's not the case now, and some authors like to speculate that it may not be true in the future.

Historically, the most common form of extended marriage was one man with multiple wives. The technical term for this is "polygyny",[[note]][[YouKeepUsingThatWord/LessPedantic "Polygamy" is a much more general term while "polygyny" is specific to one man and several wives]][[/note]] and it has appeared in a wide variety of cultures. For this reason, adventure stories set in an exotic corner of the Earth are most likely to feature polygny. To some extent, this can be TruthInTelevision; more of the world allows or at least accepts polygamy than many westerners realize.

In works set on other worlds, all sorts of extended marriages can be found, often associated with a FreeLoveFuture. Extended marriage is often shown as an element of both {{utopia}}s and {{dystopia}}s. And when it comes to exotic aliens with {{bizarre alien biology}}, all bets are off. Monogamy may not even be physically ''possible''.

Subtrope of {{Polyamory}}. The existence of this trope is often a necessity for a MarryThemAll scenario. See the Useful Notes page, UsefulNotes/ForTheLoveOfMany, for a broader discussion of the general topic.

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!! Examples:

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[[folder: Anime & Manga ]]

* In ''LightNovel/AsobiNiIkuYo'', the Catians have no issues with a male choosing multiple mates. This becomes relevant to the plot when [[spoiler:Kio's house]] is converted into the official [[spoiler:Catian embassy, leaving Kio [[MarryThemAll free to marry]] all three of the girls in love with him]].
* In the canon ''TenchiMuyo'' OVA, Juraian royalty practices just about every kind of old fashioned marriage trope out there: the Emperor has multiple wives, children are encouraged to marry their half-siblings, marrying partners several thousand years your senior (or junior) barely registers the bat of an eye, etc. These practices add some legitimacy to Tenchi's harem situation, leaving open the possibility that he could just MarryThemAll.

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[[folder: Fan Works]]

* In the [[{{Rule34}} adult]] "Human In [[WesternAnimation/MyLittlePonyFriendshipIsMagic Equestria]]" work ''Fanfic/{{Xenophilia}}'' and its clean side story ''The Xenophile's Guide to Equestria'', monogamy is considered selfish and somewhat disgraceful, and the typical romantic group starts around four people. While most groups only share flowers, rings, and/or vows rather than getting officially married, even politically important marriages still mean a single person marrying a group. Justified because of a male/female ratio imbalance--male births frequently miscarry.
* ''Fanfic/AMightyDemonSlayerGroomsSomePonies'' has [[Franchise/MyLittlePony Megan]] introducing polygamy (or more correctly, harem-like herds) among the ponies as a necessity due to the male-to-female imbalance. Over the generations, the gender ratio balances out and the ponies slowly switch to monogamy.
* Inverted in ''Fanfic/BaitAndSwitchSTO'', which mentions that the Pe'khdar don't generally practice anything resembling marriage at all. They actually expect sexual relationships to fade, and children are the responsibility of the mother's entire clan.
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[[folder: Literature ]]

* In Creator/RobertAHeinlein used this trope a few times, as part of a broader theme of {{Polyamory}} in his works:
** ''Literature/TheMoonIsAHarshMistress'' features extended marriage as a common part of life on the moon, in large part because of a shortage of women. The protagonist, Mannie, is part of what he calls a "line marriage". [[note]]The most common type of marriage is two men with one women, reflecting the relative proportions of the sexes. But Mannie's line marriage has an even balance of sexes - they started with a man and woman who added another husband, then another wife, then another husband, then another wife... Interestingly, the wives make all the decisions (though they let the husbands vote on whether to add another spouse to the marriage, which is ''not'' standard practice in their society) but the family is named after the founding ''husband.''[[/note]]
** ''Literature/{{Friday}}'' starts with the protagonist in a group marriage in New Zealand, although they divorce her after she exposes their racist hypocrisy. She later joins a much healthier group marriage.
* In Donald Kingsbury's ''Literature/CourtshipRite'', the harsh life on the LostColony of Geta has led to extended marriages being quite common. Marriages of up to six people are allowed, and a six-marriage is considered the most perfect, balanced ideal.
* In Creator/CJCherryh's ''Literature/ChanurNovels'', the cat-like Hani form prides, with one dominant male and a group of related females.
* In the ''Literature/EarthsChildren'' series, set in the distant past before the rise of civilization, most matings are one man & one woman, but sometimes a man will mate with two women, or a woman with two men. Whatever works for them.
* ''TheSharingKnife'' has a case where a Lakewalker couple couldn't have children, their families were pressuring them to break up, instead they brought a second husband into the relationship. The husbands are [[BiTheWay married to each other as well.]]
* The novella "The Outcasts of Heaven Belt" by Joan Vinge features a starship crew who are all an intermarried group (although it's usual to have a "special" relationship with just one spouse).
* Gail Dalton's ''Literature/OneRoseTrilogy'' has a society where the size of a marriage ranges from a ''minimum'' of four to a maximum of twelve.
* In Wen Spencer's ''Literature/ABrothersPrice'', a plague has left the world seriously gender-skewed, with 5-10 girls born for every boy. The solution for this is for boys to marry all sisters in a family. The hero, of course, goes on on to marry [[spoiler:all of the princesses of the realm]].
* In the ''Literature/HonorHarrington'' series:
** The planet Grayson (where Honor has dual-citizenship) allows extended marriages (polygynous, due to females greatly outnumbering males on the planet).
** Beowulf runs even more on this, having a wide variety of atypical marital and familial arrangements
* In NnediOkorafor's ''Literature/TheShadowSpeaker'', BadassPrincess Sarauniya Jaa has two husbands.
* In Creator/DavidBrin's ''Literature/{{Uplift}}'' series, uplifted chimps are often involved in group marriages, and the species known as the Gubru forms marriages in threes, and doesn't become sexually differentiated until after marriage, when one member of the threesome will become dominant and the sole female, while the other two become male.
* Vonda N. [=McIntyre=]'s ''Starfarer'' series has at least one married triad.
* In Creator/JackMcDevitt's ''Omega'' (part of the ''Literature/PriscillaHutchins'' series), the newly discovered alien race known informally as the Goompahs have a complex system of shared spouses that the researchers studying the race have a hard time figuring out. Conjugal relations are allowed throughout a particular marriage group, but most individuals seem to have one or two preferred spouses within their group.
* In Cherry Wilder's Torin trilogy, beginning with ''The Luck of Brin's Five'', the traditional Torinese family structure is built around a group of five adults, which includes at least one woman and two men in the roles we'd think of as wife and husbands. (Other roles are possible; the five adults can include grandparents as well as parents, for instance.) Biologically, each child has one mother and one father, the same as humans, but all husbands share equally in the raising of each of the family's children, and it's considered impolite to suggest that any of a child's fathers are more or less "really" its father than any other.
* In the ''Franchise/StarWarsExpandedUniverse'', it is revealed that the Cereans (the species to which Ki-Adi-Mundi belongs) have a sex ratio unbelievably lopsided towards females, and that's why they are polygamous. Even Jedi like Ki-Adi are allowed and advised to practice polygamy, since every unmarried or not married enough male is a demographical hazard to the entire race.
* In the ''Literature/{{Marsbound}}'' books, this is a rare but not unusual feature of The Future. In the second book, ''Starbound'', the selected starship crewmembers from Earth are a married triple.
* Several of the future human species in Olaf Stapledon's ''Literature/LastAndFirstMen'' practice different kinds of group marriage. The Last Men have ''96-person'' marriages that can also merge into telepathic group minds.
* In ''Literature/IslandInTheSeaOfTime'' and its sequels, most of the Bronze-Age cultures that the Nantucketers encounter believe in polygamy or polyamory. This leads to some tension between Nantucketer Marian Alston and her Fiernan partner Swindapa, as the latter is bisexual and openly ogles other men or women. Over the course of the books, BigBad William Walker acquires several wives from different cultures as a way of building alliances.
* In the ''{{Mahabharata}}'', Draupadi is married to all five of the Pandavas brothers. In a past life, she had pleased Shiva with her devotion, and he agreed to grant her anything she desired. So she asked for a husband with a long list of positive attributes. [[spoiler: Ironically, Karna is the one guy with all the attributes at once, but he can't be with Draupadi [[TypeCaste because of his social status.]]]] Shiva cautioned her that it was difficult (although not exactly ''impossible'') to squeeze all of those attributes into one man. Arjuna won her hand in a competition, made a joke about her being "alms" when he brought her home, and was told by both his mom and Krishna to share her with his brothers. She agrees to this, and there are rules, such as if she's in a room with one of the brothers, all of the others must leave. She spends a year living with each one, and the cycle begins anew. She has a child by each of her husbands, but [[spoiler: her children are all killed by the Kauravas.]] Arjuna is her favorite, but this prevents her from getting to {{Heaven}} and breaking free of the reincarnation cycle, since her duty was to love all her husbands ''equally''.
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[[folder: Live Action TV ]]

* In ''Series/{{Farscape}}'', Rygel once had many wives, before he was deposed and ended up with the rest of our refugees. Though to be fair, he was the emperor of a multi-system empire.
* ''Franchise/StarTrek'':
** ''Series/StarTrekEnterprise'': Denobulans (both male and female) tend to have three spouses each. Dr. Phlox, the ''Enterprise's'' chief surgeon, thus had a total of 720 people he was directly or indirectly married to.
** ''Series/StarTrekTheNextGeneration'':
*** In one episode the ''Enterprise'' crew has visitors from an alien race where the women are larger in stature than the men and hold all of the business, scientific, and government jobs as well as any occupations requiring physical strength. The smaller men are thought to be better suited for domestic and artistic endeavors. Important women, especially, have multiple husbands, and they all share a marital bed.
*** This trope is the alternate interpretation of a throwaway line from [[Recap/StarTrekTheNextGenerationS4E11DatasDay "Data's Day"]] that Andorian marriages consist of four people. The EU preferred the BizarreAlienSexes interpretation.
** The ''Series/StarTrekDeepSpaceNine'' episode [[Recap/StarTrekDeepSpaceNineS07E13FieldOfFire "Field of Fire"]] has a throwaway mention that a murdered [[RedShirt Gold Shirt]], a Bolian, had a wife and co-husband on Bolias.
* In ''Series/BabylonFive'' Londo Mollari has three wives, all {{Arranged Marriage}}s, whom he hates. It's apparently not uncommon for high status Centauri nobles, and made easier by their [[ExoticEquipment six "appendages".]]
* Clarice on ''Series/{{Caprica}}'' is married to multiple men and women, who are all married to each other. This is implied to be unusual but perfectly legal.
* The Nietzscheans of ''Series/{{Andromeda}}'', a genetically engineered HumanSubspecies who believe in SocialDarwinism, practice polygyny. A male can marry as many females as his displays of genetic fitness attract; alpha males often have ten or more.

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[[folder: Tabletop Games ]]

* ''TabletopGame/BlueRose'' has "star marriages", where all the participants are considered to be the spouses of all the other participants, even if they are not sexually involved with each other. They are quite common in the islands, uncommon in Aldis and almost unheard of elsewhere.
* ''TabletopGame/DungeonsAndDragons''.
** Dragon magazine #103 article "The Centaur Papers". Centaurs were said to be polygamous. The wealthier a male centaur was, the more wives he had.
** Dragon magazine #116 article "The Ecology of the Minotaur". Minotaurs are polygamous, with each minotaur bull having up to 7 females.

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[[folder: Web Original ]]

* In ''ChakonaSpace'' Chakats are [[{{Polyamory}} polyamorous]], with a saying that "love doesn't divide, it multiplies". In addition Foxtaurs and Caitians are polygynous due to skewed gender ratios (3-1 and 8-1 females to males respectively). The former two species are Terran, but uncommon enough on earth that [[InterspeciesRomance mates of different species]] have to get used to their idea of monogamy as a foreign concept.
* In the FurryWebcomic ''Webcomic/TwentyFirstCenturyFox'' the giraffes Cecil, Barb, and Beth form a "herd". Their vulpine friends find the idea of wanting to share one male a bit odd.

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