Sibling Triangle

"Primo: I saw her first.

Carlito: Carlito is the older brother, he's been here longer.

Primo: Come on, you got to let me have this one!"

- Friday Night Smackdown

In simple terms, a Love Triangle where at least two of the parties involved are siblings, who both love (or at least try to "get") the third party.

This alters the dynamic in various ways, given the famously rather complicated relationships between siblings in the first place. Might go anywhere from a friendly rivalry, one deciding that they want their siblings to be happy or straight into Cain and Abel territory. In Fairy Tales, often inspires the Bride and Switch.

If they don't hate each other from the start the Triang Relations version of the triangle is a special subset of #9.

Usually does not involve Brother-Sister Incest.

See also: Love Triangle, Two Guys and A Girl, Triang Relations, Sibling Rivalry, Settle for Sibling. When a fourth party is added, see Double In-Law Marriage.

Anime and Manga

 * Pokémon Diamond and Pearl Adventure has something similar; both Jun and his father Palmer like Mitsumi.
 * Ryou/Kyou of Clannad Also a case of Matchmaker Crush on Kyou's part.
 * Asu no Yoichi has a variant of this (Ayame likes Youichi who is kind of a pervert but seems to prefer Ibuki)
 * School Rumble has a one-sided variant: Yakumo likes Harima who likes Tenma (Yakumo's sister)
 * Rah Xephon has a more serious example with
 * In fact, there's a recursive example (two of the characters are in both love triangles) kinda, sorta with
 * Infinite Ryvius spoiler:
 * At one point in the D.N.Angel anime, both Risa and Riku are in love with Niwa. (With the added complication of Dark being in love with... One of them. It's complicated.)
 * Chocolat and Tira Misu for Carrot Glace in Sorcerer Hunters. The anime seems to go for a Tenchi Solution, but.
 * In Spiral, Ayumu was in love with his sister-in-law, and lives with her after his brother disappears.
 * In Adachi Mitsuru's Touch, twin brothers both love their childhood friend. The older backs off, allowing the younger to win at everything, including love seemingly. Then the younger dies, and the story follows the relationship that develops after this tragedy.
 * This combined with Not Blood Siblings is basically the plot of Kiss X Sis.
 * Itsuki and Sayo both fall in love with Akira in Suika. It ends when
 * In Ouran High School Host Club, manga version, both Hikaru and Kaoru are in love with Haruhi.
 * This also starts off the plot of Judge: Hiro has a secret crush on his friend Hikari, but his older brother Atsuya confessed his own attraction first, so he kept quiet about it. However, at the start of the series, he decides to tell her anyway, and secretly derails the pair's plans to meet for a date, figuring she might be more receptive to his confession if she thought Atsuya had stood her up.
 * Onegai Twins plays out like one of these. The plot consists out of two girls that turn up at a boy's house claiming to be his twin sister. The boy and the girls need to find out who is the real twin sister while falling in love with each other.
 * Simoun has an unusual example: a Type 5 triangle where Alti loves her older sister Kaimu who crushes on Paraietta who doesn't have feelings for any of them (because she's in love with Neviril).
 * Wandering Son initially had a Love Triangle between two siblings. Maho fell for a boy named Riku, so she asked her Cute Shotaro Boy brother to dress up as a girl after Riku had mistaken him for a girl and fallen for him. Even after he finds out, he seems to be somewhat attracted to Nitori; it's faded though, and he and Maho are a happy couple. It's never quite said whether Shu had feelings for Riku.
 * Brother-Sister Incest version in shojo manga Vampire Knight with both Kuran brothers, Rido and Haruka in love with younger sister Juri. Marriage between siblings is common among pureblood vampires however.
 * In Star Driver pink-haired twin sisters Mizuno and Marino You both fall for the same boy, male lead Takuto Tsunashi.
 * A variation of this can be found in The World God Only Knows, with
 * Shinshi Doumei Cross has, both in love with main heroine Haine.
 * Claudine has two.

Ballads

 * In the Child Ballad The Twa Sisters, the sister's motive in drowning her sister is jealousy.

Comic Books

 * In Ultimate X-Men, Lorna (aka Polaris) dated Scott (aka Cyclops) in the backstory, and his brother Alex (aka Havok) in the series' present.
 * In the normal X-Men continuity the Summers brothers had another one: Madelyn was married to Scott and later fell for Alex. Furthermore Scott had left her for Jean, whom it turned out Madelyn was a clone of, so...maybe this works both ways?

Fairy Tales

 * Cinderella's stepsisters have been known to cut off parts of their feeet to fit in the shoe.
 * In The Wonderful Birch, the witch made the items fit her daughter; her stepdaughter let the prince know the truth and so they used the witch's daughter to make a magical bridge and he married the stepdaughter; the witch then replaced the stepdaughter with her daughter after childbirth.
 * In The White Bride and the Black One, the stepmother murders her stepdaughter en route to the wedding and substitutes her own daughter.
 * In Chinese tale Beauty and Pockface, Pockface takes Beauty's place after she visited her family, and weeps and wails about how he never really loved her because he no longer does after she contracted smallpox.
 * In Fair, Brown, and Trembling, Trembling goes to church, and a prince falls in love with her, and out of love with Fair. After she has a baby, Fair pushes Trembling into the sea and takes her place.
 * In Tsarevitch Ivan, the Fire Bird and the Gray Wolf, after they murder Ivan, his brother draw lots about who gets to marry Helen the Beautiful.
 * In The Story of Tam and Cam, Tam is murdered by her stepmother, who gets the king to marry Cam in her place, but Tam keepts coming back.
 * In The Golden Bird, the brothers try to murder their younger brother and keep the beautiful maiden.
 * Similarly in The Golden Blackbird, The Golden Mermaid, and The Bird 'Grip'''.
 * In The Water of Life, the older brothers try to woo the princess who had agreed to marry their younger brother.

Film

 * Duel In The Sun was largely about this.
 * In the film The Man in the Moon, Emily Warfield and a very young Reese Witherspoon are sisters both in love with Jason London.
 * ~Before The Devil Knows You're Dead~
 * The Patrick Dempsey film Some Girls has a young Dempsey falling for three sisters, although he sleeps with only one and in the end doesn't wind up with any of them.

Literature

 * In the Warhammer novel Defenders of Ultuahan two brothers love the same woman. One brother leaves the other brother to die during a skirmish. This comes back to bite him in the arse.
 * In Harry Harrison's The Stainless Steel Rat Goes to Hell Digriz' two twins fall in love with the same woman. The problem is solved by going to a parallel universe and fetching an alternate version of said woman.
 * Sandy and Dennys in Many Waters both love Yalith and she loves them both back. Unfortunately, the relationship as such is doomed because the flood's coming and Yalith isn't allowed on Noah's ark.
 * Played with darkly in Hellraiser: Julia has married Larry, but eventually murders him in preference for his brother Frank, who seduced her prior to the events of the film. It doesn't really go well for her....
 * The Bible has a rather complicated example with Jacob, Rachel and Leah. Jacob fell madly in love with Rachel, and worked for her father for seven years in order to earn the right to marry her. However, in Rachel's society it was shameful for the younger daughter to be married first, so (with some help from the very thick veils used at the time, as well as some alchohol) their father switched Rachel out with Leah, with Jacob only finding out during the wedding night. Rachel and Leah's father then forced Jacob to work another seven years so he could marry Rachel for real. One can't help but wonder what poor Leah felt about this arrangement. (In a slightly unrelated note, this is why we have the tradition of the bride removing her veil in Western weddings.)
 * For an added complication, a Jewish legend says that Leah was originally destined to marry Jacob's brother, Esau, who was far less meritorious; Leah was overwrought and prayed to God, who then arranged things so she could marry Jacob as well.
 * And, to make things even more complicated, two handmaidens were involved. Who in some legends were also Leah and Rachel's sisters.
 * In the biblical fiction book The Red Tent, about Jacob and Leah's daughter Dinah, this is one of the main plot points. Jacob loves Rachel but also loves Leah. This is further complicated by the book saying that the handmaidens (Bilhah and Zilpah) are their sisters.
 * Which is true in some Jewish lore as well.
 * In the Isaac Asimov short story To Your Health, two brother opticians are in love with the same eye-fixated girl.
 * Mansfield Park: The Bertram sisters go after Henry Crawford (despite Maria Bertram already being engaged). The results: Crawford plays with their hearts for his own amusement until their Disappeared Dad returns home, goes after their cousin Fanny next because she's the only girl on the planet immune to his charms, and.
 * The four main characters of The Demons Lexicon are two sets of siblings. Of each set, one sibling is attracted to both of the other siblings. Only one of these attractions is Played for Drama; the other fizzles out as the party instead develops a crush on the Big Bad.
 * A dark version in the backstory to The Elfstones of Shannara. The Witch Sisters, Morag & Mallenroh both fell in love with a human. Given that they're a pair of Selfish Evil Yandere sociopaths, this ended with him dead, and each of them blaming the other one.
 * East of Eden (which is, after all, based on The Bible), has two of these. . Later,.

Live Action TV

 * Arrested Development played with this. Michael develops feelings for Marta who is with GOB. GOB is mostly using her but he doesn't want Michael to have her either. Also Buster has a crush on Marta. All three of them are rebuffed by Marta eventually.
 * Tommy and Justin of Brothers and Sisters were both dating Lena, though not precisely at the same time.
 * An episode of Little House On the Prairie has Laura with a crush on an older boy, who has a crush on Mary (Laura's older sister).
 * Due to Tutor's being part elf, Justin and Alex fight over her like this. While Alex's fighting for her is supposed to be platonic it has been taken in other ways.
 * In the British thriller series The Last Enemy, Stephen and Yasim start a relationship with each other after her husband (his brother) dies in a car bomb. Then the brother comes back.
 * The Vampire Diaries brings us Damon and Stefan Salvotore who became vampires after falling in love with Catherine, a vampire that abuses their love triangle. After she is killed  the brothers eventually end up in Mystic Falls where they both fall in love with Elena, who looks exactly like Catherine.
 * One episode of The Secret World of Alex Mack has Alex get a crush on a boy, who she later finds out is dating her sister. She tries to keep him from breaking up with Annie, and when he does anyway, she refuses to date him because he dumped her sister for her.
 * Probably happened more than once on Degrassi the Next Generation, but Adam and his brother Drew fought over Fiona, before Drew bowed out.
 * A weirder example is the Declan/Holly J/Fiona triangle. Because they moved around a lot Declan and Fiona were very close but after Declan fell for Holly J, Fiona did everything she could to try to drive Holly J away including kissing her brother at a party. After getting therapy, Fiona became good friends with Holly J eventually realized she’s a lesbian and was in love with Holly J.
 * One episode of Roseanne has Mark almost take a girl out on a date just because his younger brother David wanted to. His Jerkass-ery is repaid when his wife almost finds out, and David, after helping him hide it from her, asks Mark if he really wants to go out of his way to alienate the only two people who really care about him.
 * One episode of Sister Sister has a guy accidentally ask identical twins Tia and Tamara out on a date because he couldn't tell them apart. The three go on a rather awkward date together when he comes over and the mistake is realized. Both also liked Roger after he suddenly becomes hotter, and he winds up dating each of them at some point.
 * In an episode of Frasier, Frasier and Niles think they're participating in this trope as they compete for the affections of a certain woman at a party, but they realize they've been talking about two different women all night...right after they decide their sibling bond is more important than a random woman, let the object(s) of their affections leave the party without propositioning them. Cue double Oh Crap expressions.
 * In The Borgias, thirteen-year-old Joffre Borgia marries Femme Fatale Sancia, who has a torrid affair with his elder brother Juan. Incidentally, Juan was supposed to be the one marrying Sancia in the first place but he refused on the grounds that she's a mere Royal Bastard, (despite the fact that he's infamously illigitimate himself what with being the son of the Pope and all) but he doesn't mind having sex with her literally seconds before she consummates her marriage with poor Joffre. Also, while the show hasn't had time to portray this yet, historically Sancia later had an affair with the eldest Borgia sibling Cesare, making it a sibling love square (this situation is sometimes cited as the reason for ) Yeah. The term Big Screwed-Up Family barely even covers it. Particularly when you factor in the various Sibling Triangles engendered by Cesare and Lucrezia’s incestuous relationship (whether the show will actually go there remains to be seen, but so far the Incest Subtext is hardly subtle). Cesare threatened to murder her first husband Giovanni if he ever hurt her, and he.
 * Wataru, Taiga and Mio in Kamen Rider Kiva, though Wataru and Taiga initially do not know they are brothers.

Music

 * In the folk song "William and Davy", twins William and Davy fight bitterly over the woman they're both in love with... who, as it turns out, isn't interested in either of them.

Professional Wrestling

 * At the end of November 2010, both of the Bella Twins started going after Daniel Bryan in WWE Raw, with this trope being the inevitable result.

Theater

 * Verdi's Il Trovatore. And the boys don't even know they're brothers. Consequence? Well, it's an opera...
 * Other operatic examples include Pelléas et Mélisande by Debussy (based on Maeterlink's play), and Amadis by Jules Massenet.
 * A variation exists in The Love of the Nightingale. Tereus has an Arranged Marriage to Procne but falls for her sister Philomele. However neither even likes him.
 * This is basically the plot of "The Bartered Bride", the opera by Bedrich Smetana. Marenka and Jenik want to get married, but Marenka's parents have already employed a matchmaker to hook her up with the son of a rich man named Micha. The matchmaker demands Jenik break up with Marenka, and Jenik promises he will do so if the matchmaker pays him off and promises that Marenka won't marry anyone else but Micha's son. Jenik, of course, turns out to be Micha's long-lost son, and he and Marenka get married.
 * A major plot point in Blood Brothers is both Mickey and Eddie being in love with Linda. However none of the three know that Mickey and Eddie are brothers.
 * In Hamlet, Claudius murders his brother and marries his brother's wife a month later. It's heavily implied that she herself was in on the plot.

Video Games

 * In the War Craft universe, Night Elf brothers Malfurion and Illidan Stormrage both vie for Tyrande Whisperwind's affections. Illidan's rage and jealousy towards Malfurion for so effortlessly (and unintentionally) winning Tyrande's affections played a large part in triggering Illidan's Face Heel Turn.
 * And in Frozen Throne it's revealed that he still cares for her; the news of her being dead (not really) triggers a Heel Face Turn where Illidan fetches her, gives her back to Malfurion then leaves their lives for good.
 * In Persona 2: Eternal Punishment, Tatsuya and Katsuya are both in love with Maya. Katsuya's Shadow taunts him with this and uses it to try to get him to shoot Tatsuya.
 * In Dragon Age II, Hawke's younger brother Carver cautiously tries to win the affection of Merrill, one of Hawke's possible love interests. He does not succeed, as Merrill seemingly doesn't notice, but if Hawke and Merrill become a couple, in a later Party Banter Carver bitterly comments "So, you and Merrill.", to which an aggressive Hawke replies "Yes. I and Merrill". A similar situation can arise regarding Hawke's sister Bethany and Sebastian, but it is less severe, as Bethany and Sebastian don't spend much time in the party together.
 * Carver also shares a mutual attraction with Isabela, which leads to a funny reaction from Hawke when Isabela gets turned on by Carver's flirtation.

Western Animation

 * Semi-example: In one episode of Teenage Mutant Ninja Turtles, three of the four Turtles eat pizza tainted with a love potion, causing those three to fall in love with Irma. Hilarity and in-fighting ensue, until Splinter and the unaffected Turtle, Donatello, find a way to counteract the potion. Afterwards, further hilarity ensues when Irma discovers who was actually courting her.
 * Phineas and Ferb plays this for laughs on one occasion--when in the future, it's hinted that Isabella will grow up to marry her crush Phineas, much to her pleasure. Candace then points out that the hint could also mean she marries Ferb instead, causing him to suddenly start flirting with her. And needless to say, there's at least some Ferbella fanfiction that exploits this trope for drama.
 * It's also been hinted in different episodes that both Irving and Albert have a thing for Candace. This doesn't make much of a difference, though, since she only has eyes for Jeremy.
 * In one episode of Ugly Americans, Callie gets a little sister, Lillith, who plans to kill Callie and have sex with her boyfriend, Mark, most likely against his will. Made even weirder because Mark and Callie had raised her since she was a toddler (two weeks before).
 * ThunderCats (2011) establishes a triangle between adoptive siblings Lion-O and Tygra and their bodyguard/priest Cheetara, with Cheetara unaware that the brothers are jockeying for her favor behind her back. It's later revealed that Tygra and Cheetara were friends as kids, which is why Tygra took an interest in her.
 * In The Legend of Korra, Bolin has a crush on Korra, while she has a crush on his brother Mako, who likes her back but has trouble admitting it. For added confusion, Mako is dating another character, Asami.