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Best Friends-in-Law

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In fiction (not to mention Real Life), it's not uncommon for friends to be as close as family. (After all, Friends Are Chosen, Family Aren't.) For the most part, such relationships go unformalised. You might wish you could make a friend an official relative, but your options are limited. Adoption is difficult, especially when both people involved are adults. And marrying your friend probably isn't an option if you just don't feel that way about each other.

But there is another option that some characters take: marry one of your friend's relatives! Or fix it so that one of your relatives marries one of theirs. Then you'll become in-laws, which is almost as good as being blood relatives and gives you an excuse to spend vacations and holidays together. Some common variations:

  • Marry your friend's sibling, so that your friend becomes your sibling-in-law.
  • Marry your friend's child, so that your friend becomes your parent-in-law.
  • Have a child who marries your friend's child, so that you and your friend, in-laws of some sort, anyway.

Often in these situations, the romantic relationship comes off as secondary to the platonic one, with the spouse potentially being a Satellite Love Interest. Sometimes the platonic relationship may even be the primary motivator for the marriage, though it's hoped that most characters genuinely Marry for Love.

May overlap with Settle for Sibling or Double In-Law Marriage. Not to be confused with making friends with your in-laws.

Especially in modern times, when marriage rates are on the decline, a long-term non-married relationship can qualify for this trope, provided it brings two friends closer together and doesn't create tension between them.


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    Anime & Manga 
  • In Bloody Monday, Fujimaru's best friend Otoya is romantically involved with his younger sister Haruka. The two even get a double wedding at the final of the third season.
  • In Code Geass, Lelouch Lamperouge considers this a favorable outcome with his best friend/rival Suzaku Kururugi and little sister Nunnally. They might have hooked up in the end, since Suzaku (as Zero) is seen working closely with Empress Nunnally, but Lelouch (aka the original Zero) isn't around to be an in-law.
  • Fullmetal Alchemist:
    • Implied by the ending of Fullmetal Alchemist. Brothers Edward and Alphonse have grown up with their neighbor Winry, and the three are extremely close. The story ends with Edward having married Winry, making her and Alphonse this trope.
    • The non-canon "Kids" OVA of the Fullmetal Alchemist (2003) depicts three of Ed's grandkids. Two look exactly like Edward and Alphonse, while the third resembles Winry. This means that either Edward or Alphonse married Winry (or her Earth counterpart).
  • In If I Could Reach You, Uta sees her older brother Reiichi's wife Kaoru as a Cool Big Sis, since they've known each other since they were little, and doesn't realize until it's too late that she's in love with Kaoru. Kaoru and Uta's mothers are also best friends, and the latter apparently feels responsible for a medical error that cost the former her life.
  • In Itazura Na Kiss Kotoko's and Naomi's fathers were best friends since childhood. They ship the children badly (especially Naomi's mother). After some years they wish becomes true and the pair gets married.
  • Briefly discussed in Kaguya-sama: Love Is War when it's revealed that Moeha has a Precocious Crush on Shirogane (her best friend Kei's older brother). Given that this is Moeha, she's also shown fantasizing about what kind of face Kei would make if she told her that she was (hypothetically) sleeping with him.
  • Komi Can't Communicate: Komi's mother, Shuuko, and her uncle's wife, Ryouko, are extremely good friends and always ecstatic when they can spend time together.
  • Lyrical Nanoha:
    • Nanoha's older sister Miyuki became friends with Amy in the A's Sound Stages. Amy married Chrono during the Time Skip between A's and StrikerS. Nanoha and Chrono's sister Fate are a couple.
    • Nanoha and Suzuka are another example since Nanoha's older brother Kyoya and Suzuka's older sister Shinobu have been together for at least ten years by the time of StrikerS (though it's unknown if they ever got married).
    • And when you add the above two together, Fate and Suzuka also apply.
    • Amy's marriage with Chrono also provided another example due to Amy being Fate's Cool Big Sis.

    Comic Books 
  • A few Shazam! continuities have romance between Mary and Freddy, which would result in this trope for Freddy and Billy.
  • Superman:
    • In some alternate universe stories (like Superman's Pal, Jimmy Olsen #57), Jimmy Olsen got married to Supergirl, Superman's cousin. (He didn't originally know that she was Superman's cousin, having married her Secret Identity, Linda Lee Danvers, but presumably he considered it another plus once he found out.)
    • In Jimmy Olsen #56, Superman marries Lois Lane and Jimmy marries Lucy, Lois' younger sister. Their children also form a relationship in the same issue, though there's less concern about the fact that they're cousins and more about the fact that Superman's daughter being a hero herself could potentially put Jimmy Jr.'s life in danger.

    Fan Works 
  • Flower princess11:
  • In the Harry Potter AU 3 Slytherin Marauders, Snape and Lucius become this when Snape adopts Harry and Lucius marries Petunia and adopts Dudley.
  • Varric and Hawke are this by the end of Beyond Heroes: Of Sunshine and Red Lyrium.
  • In several Danny Phantom fanfics, Danny's best friend Tucker ends up marrying his sister, Jazz, making them brothers-in-law. For Tucker, this applies two-fold in situations where Danny marries Sam.
  • Happens, whether they like it or not, to Edward Elric and Roy Mustang in the Elemental Chess Trilogy. One of the stories in Notes From the Grandmaster confirms that Ed's son marries Roy's daughter.
  • JoJo New Universe: Jonathan Joestar and Robert E. O Speedwagon are just as much best friends as they are in the manga, but become in-laws when Robert would marry Jonathan's adopted sister, Lydia Twilightnote . Likewise, Lydia would also be this trope to her Childhood Friend Erina Pendleton when the latter marries Jonathan.
  • Little House on the Prairie fanfic Sylvia Webb has Albert and Sylvia's grandson, Joe Matthews, whose late wife, as he tells his own grandson, happened to be granddaughter to Albert's friend Andy Garvey (though it's not clear whether they were alive when their grandchildren married each other, only that Sylvia and her daughter fixed them up).
  • The Loud House:
    • Some fan works feature Lincoln's best friend Clyde and his older sister Lynn as a couple, although it's more common for them to be merely dating rather than outright marrying.
    • A few other fanfics have Lincoln and his friend Rusty become brothers-in-law via the marriage of their respective younger siblings (Lucy and the One-Episode Wonder Rocky).
  • Any My Little Pony: Friendship Is Magic story where Twilight marries / gets together with Applejack's brother, Big Macintosh, as many fans of the series consider Twilight and Applejack to be closest to each other among the Mane Six.
  • Sidon and Link are this in Offspring. Link is the widower of Sidon's sister Mipha.
  • In any Sailor Moon fanfic where Hotaru marries Usagi's brother Shingo (a very popular pairing), she becomes Chibiusa's aunt as well as Usagi's sister-in-law. And since the other Outer Senshi are her adoptive parents, such a union would make more than half the team family.
  • Skyhold Academy Yearbook has this as the relationship between Fenris and Bethany; Fenris is married to Bethany's sister, and it's obvious that he and his sister-in-law have a strong platonic affection between them. Later in the series, Hawke and her best friend Varric become this when he marries Bethany. Eventually, because there are so many Family of Choice relationships among the school staff members, Bull jokes about them all being related to each other in a similar manner and needing a flow chart to keep track.
  • Son of the Sannin:
    • Itachi and Shizune develop an Intergenerational Friendship early in the story, and it's through that friendship that Shizune meets her eventual husband, Itachi's cousin Shisui.
    • It's implied that Naruto and Hinata's mothers were friends back when the former was alive. Kushina's chakra ghost also mentions that she had originally theorized that Naruto would end up with the second child of her best friend Mikoto, though this was before she found out that Sasuke was a boy.
    • In the epilogue, Matsuri and her friend Sari are sister-in-laws due to them being respectively married to Gaara and Kankuro (Matsuri is specifically mentioned to have played matchmaker for the latter couple).
  • In the Death Note AU Those Who Stand for Nothing Fall for Anything Matsuda is Light's brother-in-law through his marriage with Sayu, and he thinks he and Light are this. Light, for his part, finds Matsuda to be annoying but convenient, and uses him when he needs to look sociable.
  • Ultimate Misfits: Jerrica and Pizzazz's mothers were best friends and their fathers were best friends too.
  • The Lyrical Nanoha/Sailor Moon crossover White Devil of the Moon does this with Hotaru and Alicia, who were adopted into the Takamachi and Harlaown families respectively after Nanoha and Fate had already started dating.
  • Pokémon: The Series: In many stories where Ash and Misty are the main pairing, it's not uncommon to find Tracey (one of Ash's friends) and Daisy (Misty's oldest sister) as a potential Beta Couple, thus making them this trope.
  • A Caged Songbird: In this Alternate Universe Fic where Sansa marries Joffrey, Sansa strikes up an Odd Friendship with Joffrey's uncle Tyrion, who's practically her only true friend while she's trapped in King's Landing.

    Films — Animation 
  • In Hotel Transylvania, Count Dracula tries to get Jonathan, a human tourist who found the hotel by complete accident, out of the hotel before anybody finds out about him. After various failed attempts at doing so, Jonathan ends up becoming very popular among the monsters at the hotel in his monster disguise "Johnnystein", attracting the attention of Dracula's daughter Mavis. Dracula eventually warms up to Johnny and, when the secret is out, Dracula runs off to get him back.
    • In Hotel Transylvania 2, the trope is verified when Johnny marries Mavis and becomes the father of Dracula's grandson Dennis. Here, they conspire behind Mavis's back, Johnny trying to dissuade Mavis from moving them all to California while Dracula tries to prove that Dennis is a vampire (and by extension removing Mavis's incentive to move).
  • In The Legend of the Titanic, Top Connors and Ronnie have been pals throughout the entire story, then become this at the end of the film when Connors marries Ronnie's sister Stella.
  • In the Disney version of Sleeping Beauty, Phillip's dad (King Hubert) and Aurora's dad (King Stefan) are stated to be close friends and a big reason they want their kids to marry each other is to unite their kingdoms. Fortunately, it turns out to be a Perfectly Arranged Marriage, with a touch of Dramatic Irony.note 

    Films — Live-Action 
  • Angus, Thongs and Perfect Snogging: By the end of the movie, protagonist Georgia Nicolson and her best friend Jas are each in a romantic relationship with Jennings twins Robbie and Tom respectively.
  • Anyone but You: By the end of the movie, Bea and Ben are successfully paired together and Ben's very good friend Claudia is married to Bea's sister Halle.
  • Bring It On: Torrance Shipman's Love Interest Cliff Pantone is the brother of Torrance's new teammate and companion Missy. While Missy's not exactly crazy about the idea of them together, she's not against it either.
    Missy: What did you see in my brother anyway?
    Torrance: He's your brother, you don't see him the way I do.
    Missy: And that's a good thing because that would be a crime.
  • Catherine Called Birdy (2022): Birdy willingly gives her husband's money to her brother Robert so he can marry her best friend Aelis, even though it means that she'll be trapped in an unhappy marriage.
  • CODA (2021): Downplayed. Ruby's Only Friend Gertie develops a crush on her brother Leo, and they're in full Make-Out Kids mode by the end of the movie. Ruby has mixed feelings about this, but the friendship endures.
  • The Fantastic Beasts film series shows that this eventually happens between Newt Scamander and his Muggle Best Friend Jacob Kowalski. Though Newt and Tina Goldstein don't actually get together during the course of the movies, it's canon that she eventually becomes his wife; meanwhile, Jacob falls in love with Tina's sister Queenie Goldstein, and marries her at the end of the third movie, with Newt as best man and Tina as maid of honor. Really, since the four of them become solid True Companions in the first movie, they all eventually end up like this.
  • Fifty Shades of Grey trilogy: Eventually Anastasia Steele is married to Christian Grey while Anastasia's best friend and roommate Kate Kavanaugh gets engaged to Christian's adopted brother Elliot as well.
  • Get Over It: Kelly Woods and her older brother Felix's best friend Berke Landers develop a budding romance throughout the movie, culminating in a kiss and then Felix punching Berke in the face almost immediately after. Later on during the climactic play in the movie, Kelly and Berke have their Relationship Upgrade with yet another kiss and realizing how happy they are together, Felix begins coming around to accepting it.
    Felix: So you and my sister, huh?
    Berke: You're not gonna hit me again, are ya?
    Felix: No. I mean I'm not thrilled about it, but...if it had to be anybody, I'm glad it's you.
  • Men in Black II: While Did Not Get the Girl is invoked in both cases and before the third film had it even revealed that K ever since J was little had been his Parental Substitute even long before first recruiting him as well, the reveal that K had a relationship with Princess Laurana of Zartha before she was murdered by Serleena, also comes with the implication of her daughter Laura Vasquez—whom J became involved with—being K's daughter as well—and thus J and K would become involved as in-laws of sorts too.
  • In Notting Hill, William Thacker's sister Honey clearly believes in this trope when she first meets his date, famous actress Anna Scott:
    Honey: Oh God this is one of those key moments in life when it's possible you can be really, genuinely cool — and I'm going to fail a hundred percent. I absolutely and totally and utterly adore you and I think you're the most beautiful woman in the world and more importantly I genuinely believe and have believed for some time now that we can be best friends. What do you think?
    Anna: Ahm... I think that sounds, you know, lucky me. Happy birthday.
    Honey: Oh my God. You gave me a present. We're best friends already. Marry Will — he's a really nice guy and then we can be sisters.
    Anna: I'll think about it.
  • Star Wars: Han marries Leia (Luke's sister), so becomes Luke's brother-in-law.
  • The Town: Doug has an on-off relationship with his best friend Jem's sister, Krista. Jem is actually really enthusiastic about their relationship, as it means that he and Doug are basically family. However, it's a pretty rocky one, and Doug dashes Jem's hopes that there's any future in it.
  • Wedding Crashers: Best friends John Beckwith and Jeremy Grey become this as a result of the former getting together with Claire Cleary and the latter marrying her sister Gloria.
  • White Christmas focuses on the romance between two best friends, Bob and Phil, and a pair of sisters, Betty and Judy. By the end, none of them are married but they do exchange some jokes about this.

  • Jane Austen liked this trope:
    • Emma:
      • Emma and Mr Knightley start this way, because her sister is married to his brother, and for all their little quibbles with each other they are clearly devoted friends. They take this trope further, invoking Double In-Law Marriage by getting married themselves at the end of the book.
      • Emma grows very close to Frank Churchill, whose father is married to her former governess and mother substitute, making them unofficial stepsiblings as well as good friends. Frank is also extremely close with his stepmother, so the two of them fit the trope as well.
    • In Mansfield Park, Fanny eventually marries her cousin Edmund, and the book observes that her father-in-law completely adores her and goes to great lengths to have her visit. It's something of a variant on the trope, however, since she was already his niece, and she grew up in his house so he adored her even prior to her romance with Edmund.
    • Northanger Abbey:
      • Catherine and Isabella initially hope to become this when Isabella gets engaged to Catherine's brother James. This ends when Isabella breaks James's heart and Catherine realizes Isabella's friendship wasn't quite so true.
      • Isabella also hoped to double down on this by getting Catherine together with her brother John, but Catherine was never attracted to him.
      • Catherine and Eleanor Tilney actually do become this when Catherine marries Eleanor's brother Henry.
    • Pride and Prejudice:
      • At the end of the book, Elizabeth marries Mr Darcy, and her sister Jane marries his best friend Mr Bingley. Elizabeth also develops this trope with her new sister-in-law Georgiana; the book notes that they grow to love each other dearly.
      • Elizabeth's best friend Charlotte marries Mr Collins, Elizabeth's father's cousin (the exact relationship between them is never clarified), making them a form of this trope as well.
    • At the end of Sense and Sensibility, Colonel Brandon and Edward Ferrars are shown to be in the process of becoming close friends. They're in love with the Dashwood sisters, whom they marry by the last page, and the narrative explicitly describes them as becoming excellent friends even prior to the weddings because they have so much else in common, too.
  • Bazil Broketail: Played straight with Eilsa's father Ranard, who comes to respect Relkin as a man and a warrior during their fight against the Padmasan invasion and approves of his relationship with his daughter. Averted with all her other relatives — especially her aunt Kiri — who despise Relkin for who he is and constantly try to discourage Eilsa from marrying him, offering her better situated and wealthier candidates.
  • No one comes out and says it, but at the end of the Belgariad Durnik, Garion's oldest friend, technically becomes his uncle by marrying Polgara.
  • In The Big Wave, Kino and Jiya are childhood friends, and Jiya grows up to marry Kino's sister, Setsu.
  • In the Billabong series of Mary Grant Bruce, Jim and Wally are best friends and then become brothers-in-law when Jim's younger sister and Wally fall in love and get married.
  • The men in A Brother's Price hope for this and/or deliberately try to bring it about, as they can expect to see their family of origin much more often if the families are friends. For Ren, however, the marriage to her best friend's brother didn't work out so well; although Ren was good friends with Kij Porter, it turned out Keifer Porter's death was not a source of grief for any of his wives.
  • Bridget Jones: The parents of Bridget and Mark have been close friends for a long time and have been trying to set the two up together. They fail, succeed, and fail until succeeding again.
  • Dancing Aztecs: Mel, Frank, and Floyd are the husbands of Jerry's two sisters, and Frank's brother respectively, and the four get along pretty well, run various scams together, and are equal partners in the statute hunt.
  • It's implied near the end of The Elenium that Sparhawk's daughter Danae will marry his squire Kurik's son Talen. Kurik has died by this point, so it's too late for him to be this trope with Sparhawk, but Sparhawk also considers Talen himself a friend so the trope will apply to them.
  • Laurie Polk, the protagonist of one story in the Genre Anthology mystery collection Five-Minute Mysteries 3: another 40 cases of murder and mayhem for you to solve, is investigating the death of his brother-in-law Trent. Trent was Laurie's best friend since first grade and had a Childhood Friend Romance with Laurie's sister before marrying her. Consequently, Laurie is utterly devastated when he uncovers proof that his sister and an acquaintance almost certainly conspired to trick their respective spouses into getting trapped in a blizzard and freezing to death.
  • The Great Greene Heist: Charlie and Jackson have been best friends and partners in crime since before Charlie's sister Gaby and Jackson developed feelings for each other.
  • At the end of the Harry Potter series, Harry becomes brother-in-law to both of his best friends: Ron and Hermione get married and Harry marries Ron's sister, Ginny. This was referenced by the fandom even before it became canon; the Idiosyncratic Ship Name for this set of pairings is "One Big Happy Weasley Family." Since it's implied in the books that Ginny is Hermione's closest female friend, this arrangement makes them best-friends-in-law as well.
  • The Lawrence Block short story Keller on Horseback features a man who married the daughter of his best friend and surrogate father, Lyman Crowder. This is deconstructed though, as their marriage becomes an Awful Wedded Life but neither can bear to disappoint Crowder by getting a divorce, so someone who wants them to get divorced hires a hitman to kill Crowder.
  • In the Little Women series, Laurie eventually agrees with his best friend Jo that they're too similar to ever be happy as husband and wife. His Second Love is Jo's youngest sister Amy, and Jo names her second son "Teddy," after her pet name for Laurie.
  • In the appendices to The Lord of the Rings, Sam's daughter Goldilocks marries Pippin's son Faramir.
  • Lord Peter Wimsey's Friend on the Force, Charles Parker, falls in love with Wimsey's sister Lady Mary during Clouds of Witness and later marries her.
  • Mitch Tobin: Ernie Rembek's brother-in-law Frank Donner is a trusted crony of his and a member of his crime syndicate.
  • My Next Life as a Villainess: All Routes Lead to Doom!
    • Catarina has this relationship with two of her Childhood Friends. Mary is engaged to Alan, the twin brother of Katarina's fiance Geordo. This gets complicated since in the series which royally put the game off-rails thanks to Catarina's change of personality and her active ways to avoid her doom, Mary and Alan have feelings towards Catarina, which Geordo doesn't appreciate. Meanwhile, Sophia actively tries to hook Catarina up with her older brother Nicol, who has feelings for her but doesn't act on it out of respect for Geordo.
    • This also applies within the unaltered game scenario as well. From what little Catarina knew of Nicol's route, getting the good ending requires the player to have a very close relationship with Sophia.
  • In Överenskommelser by Simona Ahrnstedt, Beatrice/Seth and Sofia/Johan have this kind of relationship. Beatrice and Sofia are cousins, while Seth and Johan were close friends even before they met the Löwenström girls. Magdalena and Gabriel in "De skandalösa" have a similar relationship with Gabriel's sister Nora and her gay lover Venus.
  • The Scholomance: Chloe's father (an indie kid) and her maternal uncle (an enclaver) were allies when they attended the Scholomance together. Her uncle introduced her dad to his sister after they made it out alive, leading to their marriage.
  • Common in A Song of Ice and Fire, since the setting's tradition of Arranged Marriage is explicitly intended (at least in theory) to promote stronger ties between already-friendly nobles.
    • The backstory has Ned Stark and his friend and mentor, Jon Arryn, marrying the Tully sisters, making them brothers-in-law.
    • Robert Baratheon was supposed to marry childhood best friend Ned's sister Lyanna, which would have made them this. That fell through when Rhaegar Targaryen kidnapped her, leading to Robert's Rebellion and her death during it.
    • Robert tries to invoke this trope by arranging marriages between his sons Joffrey and Tommen and Ned's daughters Sansa and Arya, explicitly comparing it to the betrothal between himself and Lyanna. Of course, there's also a political motivation; he wants Ned to accept an appointment as King's Hand, and this is a way of sweetening the deal.
    • Ser Loras Tyrell and Lord Renly Baratheon aren't "just" best friends, of course, but the trope still applies: Ser Loras brokers a marriage between his sister Margaery and Lord Renly because, among other reasons, Loras will have a good reason to spend a lot of time with Renly.
  • In Sorcery and Cecelia, Kate marries Thomas Schofield, while her cousin Cecelia marries his best friend James Tarleton. The two couples have a double wedding where, in addition to being brides and grooms, they also fulfill the roles of each other's best man and maid-of-honor!
  • In the Star Wars Expanded Universe, this trope becomes canon for Luke and Han Solo. Leia is likewise good friends with Luke's wife Mara Jade.
  • Played with in War and Peace. While Natasha is engaged to Marya's brother Andrei, she and Marya get off entirely on the wrong foot. Then when Andrei is killed, they bond in grief over his death, eventually becoming best friends. Ultimately played straight, because Marya winds up marrying Natasha's brother Nikolai.
  • Crime and Punishment: Razumikhin ends up married to his friend Raskolnikov's sister Dunya.

    Live-Action TV  
  • Subverted with Jim and Andy in According to Jim: They didn't start off as friends but become this after Jim marries Andy's sister. Jim is also really close to his mother-in-law, to the point where Andy thinks she prefers him as a son.
  • In the pilot episode of the original Battlestar Galactica, Apollo and Starbuck were heading this direction when the latter was planning to be sealed to Athena, but then he broke it off with her following the Destruction of the Colonies. Apollo seems to understand this for the most part, knowing him...
  • Inverted in Breaking Bad; there's no indication that Hank and Walt were ever friends before marrying sisters Skyler and Marie, but by the time of the series, Walt has no closer male friend, and Hank's only other close male relationship is Steve Gomez. It makes it heartbreaking when Hank finds out about Walt's drug dealing, especially since Walt continues to consider Hank "family" and one of the few people for whom he would never consider arranging a convenient "accident", even if the alternative is being caught or killed himself.
  • On Doctor Who, the Doctor marries River Song (a.k.a. Melody Pond, Amy and Rory's daughter from the future). Amy (who predicted the match a season and a half earlier) has a funny moment when she realizes that, as a result of it, she's now the Doctor's mother-in-law!
  • Friends:
    • Ross witnesses Chandler having sex with his sister Monica and angrily declares, "I can't believe it, my best friend and my sister!" When Chandler and Monica explain that they're in a serious relationship and in love and not just fooling around, Ross repeats it, only this time overjoyed. Of course, he was taking anti-rage drugs at the time.
    • When Ross and Rachel start dating, Monica almost name-drops the trope, saying she and Rachel will be "friends-in-law".
  • Game of Thrones:
    • King Robert Baratheon seemed to have something like this in mind when he visits his Fire-Forged Friend Lord Eddard Stark, to both name him The Consigliere and to suggest marrying Ned's daughter Sansa to Robert's "son" Joffrey when they come of age (in truth, Joffrey is the incestuous offspring of the Queen and her brother, but Robert doesn't know that). Since Joffrey is in fact a total psycho, this didn't come to pass, and both Robert and Ned are killed off well before any marriage ceremony can take place. Posthumously, Robert's bastard son Gendry does become intimate with Ned's second daughter Arya.
    • Considering that Ser Loras Tyrell had dreamed of marrying his boyfriend Lord Renly Baratheon from a very young age (Renly is the "bride" in "green and gold brocade" — Renly wore a green brocade cloak to show his support for Loras at the jousting match), becoming brothers-in-law by Renly marrying Margaery was the only viable way for Renly to become part of Loras's family (and not Loras becoming part of Renly's family - there is a distinction), in addition to being motivated by politics. Since he was a young teen, Loras had hoped to make this fantasy come true in some form, and his family's lofty ambitions would later become the perfect excuse to permanently bond Renly to the Tyrells. Margaery is even willing to share Renly with Loras if it helps to get her pregnant. In the novels, Renly continued to use the traditional yellow-and-black sigil of House Baratheon after he declared himself king, but his TV counterpart adopts the green and gold of House Tyrell for his banner, which is Renly's way of demonstrating to Loras that he is indeed a Tyrell at heart if not in name, because Highgarden's colours are now his own. Loras makes a Freudian Slip in "Valar Morghulis" ("My sister Margaery, her husband was taken from us before...") which proves that he considers Renly to be his "husband."
    • Margaery attempts to invoke this with her dear friend Sansa Stark, by trying to set up a betrothal between Sansa and Loras. The Lannisters interfere before it can get very far, but the girls enjoy the idea while it lasts.
  • Girl Meets World:
    • While there's no technical relationship between them, Riley Matthews calls her father Cory's Heterosexual Life-Partner "Uncle Shawn." When Shawn Hunter begins dating Riley's best friend Maya Hart's mother Katy, she's overjoyed that they're going to be family.
    Riley: We were like sisters, and now we'll be cousins! * Beat* Wait a second. That's less.
    • Basically everyone has this connection by the end of the series with Riley and Maya's Love Interests being Lucas Friar and Riley's Uncle Josh respectively (with Josh only being a few years older than the girls for context). Maya would in turn become sister-in-law to both Cory and Topanga as well. That would also mean she’d be Riley's aunt—as comedically pointed out early on in the series, Lucas would be Maya and Josh's nephew-in-law and Cory; Topanga and Riley would now all be in-laws to Shawn and Katy as well.
  • The series finale of The Golden Girls does a version of this for Blanche and Dorothy. The divorced Dorothy gets married to Blanche's widowed uncle, making them step-aunt and step-niece as well as best friends.
  • Blair and Serena on Gossip Girl become this after Blair marries Chuck, Serena's adoptive brother.
  • On Heroes, Hiro's best friend Ando has been in love with/crushing on his older sister Kimiko since they were kids. Thanks to some meddling in the past by Hiro, Ando and Kimiko are engaged and Hiro is absolutely delighted.
  • iCarly & the 2021 revival: Spencer Shay's already pretty good friends with sister Carly's best friend Freddie Benson—and thus Creddie becoming canon would indeed make Freddie and Spencer this as a result too.
  • On Little House on the Prairie, Charles Ingalls' oldest daughter Mary has a romance with John Jr., whose adoptive father Isaiah Edwards is her father's closest friend, and by Season 3 they make plans to get married after John finishes college. Unfortunately, John's interest in Mary vanishes while he's living far away in Chicago, and the engagement ends, and later in the series, he' killed during a street accident which turned out to be involved with city corruption.
  • On The Marvelous Mrs. Maisel, Imogene suggests to her bestie Midge that they set up their two young children.
  • The Middle:
    • In Season 8, after several episodes building it up and having them fall for each other, Axl Heck and Lexie Brooks (Sue's roommate and best friend) begin a romantic relationship.
    • Throughout the show, Sue in turn is given Ship Tease with neighbor Sean Donahue, who is her older brother Axl's best friend as well and at some point, dates Axl's other best friend Darrin McGrew too.
  • Modern Family sets this up by its very nature:
    • All twelve leads are immediate family and very close to all the others, so this happens whenever there's an in-law relationship. In particular, Phil and Mitchell, and Claire and Cam are siblings-in-law who enjoy spending time together independently of the rest of the family to pursue particular interests or hobbies. Phil and Cam might also count in this regard since they're married to siblings from the same family and often hang out together.
    • Jay shares this relationship with one son-in-law (Cam) but not the other (Phil). Poor Phil obviously feels snubbed by this, though it becomes increasingly apparent that Jay cares for him much more than he lets on; to be fair, he's often harsh to Cam too (particularly when referring to him as "my son's friend" in front of his buddies), and only really bonds with him over their shared love of sports.
    • One of the reasons Phil is such a big Shipper on Deck for Haley and Andy is clearly that he would like nothing better than to have Andy as a son-in-law. The feeling is obviously mutual, as Andy idolises Phil.
  • Herman Munster and his father-in-law Grandpa in The Munsters are prone to getting involved in various schemes and shenanigans, usually behind Lily’s back. This carries over in The Munsters Today, but is subverted in that Grandpa possesses a more spiteful opinion of Herman.
  • The O.C.: Taylor and Summer might well be heading for this, judging from the look the former exchanges with Ryan at the latter's wedding to Seth during the series finale's Flash Forward, Ryan and Seth being foster brothers.
  • Princess Returning Pearl:
    • Xiao Yan Zi marries her best friend/sworn sister Zi Wei's brother, Yong Qi. Yong Qi's good friend Er Kang also marries his sister Zi Wei.
    • Then Xiao Jian, Xiao Yan Zi's brother and thus Yong Qi's brother-in-law, later marries Yong Qi's cousin.
  • Scrubs:
    • In the finale, J.D. pictures his and Kim's son, Sam, and Turk and Carla's daughter, Izzy, all grown up and revealing to him and Turk that they're engaged to get married. Cue Squeeing J.D. and Turk. Notable in that, unlike J.D.'s other fantasies, this is part of a montage that J.D. and the finale strongly imply will eventually happen. Given by season 9, two of his visions from that montage (his and Elliot's wedding, and her being pregnant with his second child) have happened already, it probably will.
    • Dr. Cox and Ben Sullivan were this. Their friendship withstood Cox's divorce from Ben's sister.
  • In an alternate timeline on Star Trek: Voyager, Harry Kim marries the daughter of Tom Paris and Kes, the latter from a species that only lives nine years, and so grows up quickly.
  • Olivia and Grandma Walton are this on The Waltons. While their husbands, who are father and son, will frequently butt heads, it's very rare for the two women to be anything but respectful and affectionate toward each other. Grandma doesn't have a daughter, and Olivia has no apparent relationship with her own parents (they never appear on the show and are almost never mentioned), so they are mother and daughter in all but name.
  • In the intended Series Finale of Will & Grace, Will and Grace themselves become this after their children marry, which turned into All Just a Dream when the series became Un-Cancelled in 2017.


    Myths & Religion 
  • In The Bible, not-yet-King David marries Michal and is best friends with her brother, Jonathan. To complicate matters, their father, Saul, wants to kill him.
  • In the Book of Ruth, Ruth has a great relationship with her mother-in-law, Naomi, even after Ruth's husband dies. This is the source of the famous "where you go, I will follow" quote, by the way.
  • In Classical Mythology, Orestes was raised alongside his cousin, Pylades, after his mother and her lover tried to kill him as a child. Pylades accompanies him throughout his revenge quest and subsequent madness, enduring exile from his own homeland and even offering to die in Orestes' place in Iphigeneia in Tauris. Orestes' sister Electra is also with them through most of these ordeals, and Apollo himself instructs them to get married.
  • According to biographies, The Prophet Muhammad became son-in-law to four of his companions. Muhammad himself became father-in-law to another companion, Ali, who married his daughter Fatima (note that Ali was already Muhammad's cousin; the marriage only brought the familial connection closer).

  • The conclusion of The Importance of Being Earnest implies this will be the case for protagonist Jack and his best friend Algernon, as Jack plans to marry Algie's cousin Gwendolen and Algie is going to marry Jack's ward Cecily. Somewhat zig-zagged by The Reveal that Jack himself is also Gwendolen's cousin - he's not just Algernon's best friend, but his long-lost older brother. The trope is still in play for Cecily, however, who will become sister-in-law to her legal guardian, whom she adores.
  • Westeros: An American Musical, being a A Song of Ice and Fire spinoff, includes Renly's The Beard being his same-sex lover's sister, making the two lovers brothers-in-law.

    Video Games 
  • Dragon Age has a couple:
    • It hasn't really come up in the games themselves, but the first tie-in comics for the series give this relationship to Varric Tethras and Maevaris Tilani. Mae was betrothed to Varric's cousin Thorold, who was killed before the marriage could take place; but by the intricacies of dwarven inheritance law, she is nevertheless considered his widow, and it's clear that Varric regards her as family and they are good friends.
    • In the backstory of the royal family of Ferelden, Calenhad Theirin - the first king of a united Ferelden - was married to Mairyn, the daughter of Arl Myrddin, one of his most loyal supporters and closest friends. They were this trope for the first several months of the marriage; unfortunately, it did not end happily. The pregnant Mairyn discovered Calenhad's infidelity with his general, Lady Shayna (a love potion is said to have been involved) and fled to her father, who later killed Lady Shayna. Calenhad reluctantly challenged Myrddin to a duel to avenge her, and Myrddin was killed.
  • The Elder Scrolls V: Skyrim has a few potential cases of at least friends-in-law:
    • The Dragonborn can befriend Annekke Crag-Jumper by doing a quest for her (as indicated by it becoming possible to recruit Annekke as a follower). The Dragonborn can then make her this trope by marrying Sylgja, Annekke's daughter.
    • The Dragonborn can also befriend Vilkas and Farkas, two members of the Companions guild, who are fraternal twins and potential followers; both become candidates for marriage after the guild storyline is completed, and if the Dragonborn marries one, this can be implied with the other.
    • The Dragonborn can become regarded as a good friend by Lucan Valerius by recovering the Golden Claw from Bleak Falls Barrow for him. They can then resolve the quest "A Lovely Letter" by taking the third option of marrying Lucan's sister Camilla, making them this trope. (Unlike the other potential friends-in-law, Lucan is not a potential follower because he's a merchant.)
  • Happens fairly often in Fire Emblem ever since Genealogy of the Holy War introduced the Love System (which later evolved into the support system from The Binding Blade onward):
    • Fire Emblem: Genealogy of the Holy War:
      • In the game, Quan is married to Sigurd's younger sister Ethlyn. The two of them have been friends (along with Eldigan) since their days at the military academy.
      • In Generation 2, Sigurd's son Seliph can potentially end up with Lana, Larcei, or Nanna (or their replacement characters Muirne, Creidne, or Jeanne). All three of them are the sisters of his respective childhood friends Lester, Ulster, and Diarmuid (or Deimne, Dalvin, and Tristan). Larcei is also the cousin of Seliph's Big Brother Mentor, Shannan. Naturally, any possible pair-up of this group will result in this. Nanna (who can also end up with Quan's son Leif) is also Eldigan's niece, so it's a double example. It's also possible to hook up the children of Azelle and Lex, or Alec and Naoise. While it's very tricky, it's also possible to pair Seliph's half-sister Julia up with any of the possible male characters.
    • Tragically averted in Fire Emblem: The Binding Blade, Eliwood's son Roy and Hector's daughter Lilina are each other's main love interests (Eliwood and Hector being Heterosexual Life-Partners in the prequel), but by the time they can potentially get married Hector is dead.
    • In Fire Emblem: The Blazing Blade the best friend duos of Sain and Kent or Eliwood and Hector can become this if they both marry one of the Pegasus sisters Florina, Fiora, and Farina.
    • Fire Emblem: The Sacred Stones:
      • Tana and Eirika are best friends, whereas Innes and Ephraim are rivals. If Eirika marries Innes or Tana marries Ephraim...
      • Kyle and Forde, who are also rivals (albeit of the more friendly kind), can end up as this if they marry the Frelian sisters Syrene and Vanessa respectively.
    • Fire Emblem: Awakening:
      • The Avatar and Chrom are this if a male Avatar marries Lissa, Emmeryn, Lucina, or Cynthia or Kjelle if either of them are Chrom's daughter. A female Avatar and Chrom are this if she marries Brady or Inigo if either of them are Chrom's son. Lissa and Maribelle are this if Maribelle marries Chrom, and Chrom and Vaike can be this if Lissa marries Vaike. The indirect version is attainable if any of the Avatar's children marries one of Chrom's kids, like a non!Chrom Male Morgan marrying Lucina or either of Lucina's potential little sisters, or a Female Morgan marrying a Chrom!Inigo or a Chrom!Brady.
    • Fire Emblem Fates:
      • Due to time distortion shenanigans, the male Avatar can marry the Cute Clumsy Girl Sophie, who is the daughter of their good friend Silas.
      • Silas can also marry one of the Avatar's sisters: Hinoka, Sakura, Elise, or Camilla. They're all Not Blood Siblings to the Avatar, as it turns out, but the Avatar is close enough to their Hoshidan and Nohrian siblings that it feels like this trope in play.
    • Fire Emblem: Three Houses has an interesting example. If Raphael reaches an A support with Ignatz, their paired ending has Ignatz marry his sister (who is mentioned but never physically appears in the game).
  • Galaxy Angel II has this potentially happening depending on the player choices regarding Tact and Kazuya. The player decides who is Tact's wife from the Galaxy Angel original trilogy, and depending on who Kazuya ends up romancing, he can end up as Tact's brother-in-law if he pursues Rico and Tact is married to Milfie, or as his son-in-law if he pursues Nano-Nano and Tact is married to Vanilla.
  • In Guilty Gear, as heavily implied throughout the series (and all but outright confirmed in -REVELATOR-), there's Ky and Sol, due to Ky being "married"  to Sol's daughter Dizzy. They try not to think about it too hard, judging by their reaction when they did connect the dots.
  • In The Legend of Zelda: Breath of the Wild, this was almost the case with Link and Prince Sidon, as Sidon's sister Mipha was in love with Link. But Mipha was killed before she could present the Zora Armor to Link to make any marriage promise official. Played with even further in that Sidon doesn't really get to know Link until a century after Mipha's death; nevertheless, his sister's feelings, combined with Link's heroics against Divine Beast Vah Ruta, still result in Sidon coming to view the Hylian as his best friend.
  • Story of Seasons (2014) has a few opportunities for the player to become friends-in-law with various characters:
    • The male player character can become friends-in-law with Veronica, who more or less runs Oak Tree Town, by marrying her daughter Angela. In fact, in order for the romance with Angela to progress to the marital level, the player character must have a good friendship level with Veronica.
    • Similarly, if the male player character wants to marry Lillie, it's necessary to have a very good relationship with her adorable little sister Melanie. A good friendship with Lillie and Melanie's father Morris isn't required, but it's almost impossible to avoid whether you're romancing his daughter or not, so marrying Lillie invokes this trope with him as well.
    • A good friendship with Melanie is also required for a female character who wants to romance either Nadi or Kamil, who both view the child as something of an adopted little sister.
    • If the player character marries either Iris or Mistel, they can become friends-in-law with the other sibling.
  • In Ys: The Oath in Felghana, the Player Character's best friend (whose homeland/hometown the game's set in) mentions this trope in regards to his childhood best friend Chester's sister, then notes that she'll probably end up with The Hero.

    Web Animation 
  • Etra chan saw it!: One story has Yuri and Tsutsuji as childhood friends who grow up to marry each other's older brothers. Tokusa is Yuri's older brother and Katsura is Tsutsuji's older brother.
  • Otakebi: Mami is in a good relationship with her mother-in-law. The women become closer after they get a divorce from their respective husbands and Mami considers her ex-mother-in-law to be the only family she has.
  • Revenge Films: "An important dress that my mother sewed for me was ripped in half..." - Ali's mother-in-law treated her like a real daughter unlike her father-in-law and her sister-in-law Blair.

    Web Comics 
  • Cursed Princess Club: King Jack of the Pastel Kingdom and King Leland of the Plaid Kingdom have been friends since they were young men. The main story arc starts when the two decide to arrange marriages between Jack's daughters and Leland's sons.
  • Roommates has Aisling clearly hoping for this between Sarah and her brother, Jareth. She's shown to be one of Sarah's friends in college and calmly foils Odile's stalking of Sarah on the grounds that "She's going to be my sister."

    Western Animation 
  • On American Dad!, one of the only recurring Love Interests that Steve has is his friend Toshi's younger sister Akiko. His other friend, Snot, sometimes has a Precocious Crush on Hayley, though not much comes of that.
  • Avatar: The Last Airbender and The Legend of Korra:
    • Played straight with Aang marrying his friend Sokka's sister, Katara.
    • Averted with Aang and Katara's son, Tenzin. He was in a long-term relationship with Lin, the daughter of their friend Toph, so it's likely the parents expected this trope to eventually happen; but the pair broke up and Tenzin married someone else.
    • The original series has a version of this: Sozin and Roku were best friends early in their lives. Later, Sozin's grandson Ozai married Roku's granddaughter Ursa. However, neither the friendship nor the marriage ended happily...
  • The Flintstones animated special I Yabba-Dabba-Do centers around Pebbles and Bamm-Bamm getting married, making the Flintstones and Rubbles in-laws.
  • My Little Pony: Friendship Is Magic: Twilight Sparkle had Princess Cadance as a foal-sitter and considered her a friend, but they fell out of contact. The next she hears from Cadance is a wedding announcement — and the groom is Twilight's older brother Shining Armor.
  • The Scotsman tries to invoke this in the series finale of Samurai Jack by offering Jack the hand of any one of his many daughters in marriage. Jack turns him down due to already being in a relationship with Ashi.
  • In The Simpsons Flash Forward episode "Holidays of Future Passed," Lisa has married Bart's lifelong Best Friend Milhouse. It's a less-than-idyllic example as the two are at a dry spell in their marriage and she wonders if she should have married Nelson—which means that her other option would have been Bart's other best friend.

    Real Life 
  • A variation with Sun Ce and Zhou Yu, who married the Qiao sisters.
  • Wrestlers Barry Windham and Mike "Irwin R. Schyster" Rotunda
  • Joaquin Phoenix and Casey Affleck, formerly (the latter was previously married to the former's younger sister).
  • Jean Lannes's motivation for asking Napoléon Bonaparte's sister Caroline in marriage was not so much that he loved her, but because he wanted to be closer to the Corsican general he saw as one of his best friends. In the end, she married another of her brother's generals, Joachim Murat, and they became king and queen of Naples. General Marmont inverted this: when Bonaparte offered to let him marry Pauline, another of his sisters, Marmont refused on the grounds that he was not genuinely in love with her. (Though when he saw the fate of the man Pauline eventually married, who died of yellow fever in Santo Domingo, he said in retrospect that he did not regret turning her down.)
  • John of Gaunt and Geoffrey Chaucer, both members of the court of King Richard II of England and apparently close friends, were married to sisters Katherine and Philippa de Roet, respectively. Incidentally, this makes Chaucer the great-umpty-great uncle by marriage of every British monarch since Henry VII (a descendant of John of Gaunt and Katherine de Roet on his mother's side).
  • Henry VIII and his best friend, Charles Brandon, Duke of Suffolk, became this. Charles was the second husband of Princess Mary, Henry's favorite sister. Her brother had promised her that as a reward for acquiescing to her arranged first marriage, she could have a say in the second once she was widowed; she was a teenager when she married the elderly King of France, so her widowhood was all but assured. However, it's alleged that Mary didn't trust Henry not to promise her to someone else, so she convinced Charles to marry her secretly. Henry was not pleased, but he adored his sister and Charles was his best and most trusted friend, so he forgave them pretty quickly. Charles's marriage to Mary ended with her death, and he later remarried, but he and Henry remained the best of friends for their entire lives.
  • Princess Marie-Louise of Savoy, the Princesse de Lamballe, is best remembered by history for having been a close friend of Marie-Antoinette (and being beheaded as part of that whole mess). She had this going with her father-in-law, the Duke of Penthièvre, who even consoled her when his son was unfaithful to her on more than one occasion. Her husband died less than two years after their Arranged Marriage, and she intended to become a nun, but she and the Duke were such great friends that he persuaded her to instead remain in the family home and for all intents and purposes be his daughter. She agreed, joining him in much of his charity work, and they remained close until she was killed in the French Revolution.
  • Alexander the Great and his right hand Hephaestion married two daughters of Darius of Persia, Stateira and Drypetis. It's stated that Alexander invoked this trope because he wanted to be uncle to Hephaestion's children.
  • This was one of the biggest motivations for marriage for most of human history, to create alliances by marrying their children and creating kinship.
  • Until he got married and moved to North America, this seems to have the relationship between Prince Harry of the United Kingdom and his sister-in-law Catherine, Duchess of Cambridge. They were often seen in public together and appeared to be great friends as well as family.
  • Cicero and his best friend/classmate Titus Pomponius Atticus were famously as close as brothers. They became related by marriage when Cicero's brother married Atticus's sister.
  • Alfred, Lord Tennyson and Arthur Hallam, the subject of his famous poem "In Memoriam A.H.H.," were almost this, as Hallam was engaged to Tennyson's sister Emilia at the time of his tragic death from a brain hemorrhage at the age of 22. (Tennyson and his brother Charles were also married to sisters, Louisa and Emily Sellwood.)
  • Robert Irwin, son of Steve Irwin, and his sister Bindi's husband Chandler Powell are the best of friends and work closely together at Australia Zoo. The three (four now with the birth of Bindi and Chandler's daughter Grace) are virtually inseparable.
  • Lindsay Ellis and her former roommate/collaborator Elisa Hansen became this when Lindsay married Elisa's brother Nick.
  • Vice Presdient Al Gore's best friend is his older sister, Nancy's husband, Frank Hunger. They only became closer after Nancy's death.