Runaway Bride

"She walked away from a happy man I thought I was so cool, ''I just stood there whistling "There goes the bride" as she walked out the door."

- They Might Be Giants, "Lucky Ball and Chain"

A Wedding Day trope, focusing on the bride who abandons her groom at the altar, either to be with her new flame or to celebrate her independence. This often occurs at the climax of the movie, and is frequently treated as being a heartwarming and positive affirmation of the power of True Love/Independent Women for the would-be bride. The fact that it's also a humiliating, heartbreaking, psychologically-scarring betrayal for the would-be groom tends to be glossed over. Often occurs after the priest has said, "Speak Now or Forever Hold Your Peace."

Alternately, we get stories focusing on the heartbroken bride who is left at the altar, and the absolute cad who ran away and left her there.

This trope could be the result of societal expectations. Men are expected to have cold feet before a wedding, stereotypically speaking. It's supposed to be more shocking when it's the woman who backs out to be free and single, or run away with another man. Since this offers zero comfort to the poor schlub who just got dumped in front of his family and friends on his big day, writers are careful not to develop the would-be groom too much--or they flat-out make him the villain--to keep audiences from sympathizing with him and calling her out on her recklessness.

While it is more common in modern works for it to be the woman who is viewed sympathetically, whether she is the runaway partner or the jilted-at-the-altar partner, there are plenty of cases of it being played the other way. Generally, it depends on the gender of the protagonist.

If these characters think a bit more and made their escape before the ceremony, they become Runaway Fiancé(e)s instead. Less humiliating for the other parts implied, but not that much.

If you were looking for the Doctor Who episode, see here. The Julia Roberts movie can be found here.

Anime and Manga

 * Full Metal Panic!'s Melissa Mao tells a story about her dealing with an unwanted Arranged Marriage by dumping the groom at the altar and joining the Marines. In her wedding dress.
 * For added fun it's mentioned that the guys at the recruiting station were a little leery of inducting a girl in a wedding dress, until she mentioned that her father (who'd arranged the marriage) was a colonel in the Air Force. After they heard that, they signed her right up just to spite him.
 * In the Virtua Fighter anime, Pai Chan is being chased by a Corrupt Corporate Executive who wants to marry her. Then, after she runs away, she bumps into Idiot Hero Akira Yuki and asks him to help her keep her unwanted suitor at bay...
 * In Yes! Pretty Cure 5, Komachi wants to almost marry someone she doesn't really love, then become a Runaway Bride via a Speak Now or Forever Hold Your Peace type situation, because it'd be really dramatic if that happened. Seriously.
 * Gankutsuou has Eugenie, who was being forced to marry Andrea (who was forcing the issue out of revenge, and also because he's a sick man who ). Luckily for her, Albert and Peppo disguise themselves as maids, and manage to stop the wedding by helping Eugenie run away from Andrea at the altar.
 * One episode of The Idolmaster involved a girl running away from an Arranged Marriage, and hilarity ensuing when she runs into Azusa, who is doing a wedding-themed photo shoot.

Film
"Linda: I don't need more time, Robbie. I don't ever want to marry you. Robbie: [deep breath] Gee. You know that information...really would've been more useful to me YESTERDAY!"
 * The trope takes its name from Runaway Bride, a Julia Roberts movie about a woman who repeatedly does this.
 * Real Life: Julia Roberts dumped Kiefer Sutherland a few days before their wedding for his friend Jason Patrick... Not at the altar, but that is kind of ironic appropriate, that 8 years later, she took such a role...
 * Clarisse runs away in The Castle of Cagliostro. Her husband-to-be was the lecherous, evil Count Cagliostro.
 * The protagonist of Crouching Tiger, Hidden Dragon, already a Rebellious Princess type, flees from her new marriage the day after. Of course, anyone who has seen this long cinematic piece probably forgot this by the end of the movie...
 * Spider-Man 2 plays it straight: Mary Jane abandons her groom at the altar for Peter. It comes across as particularly crass as she didn't even tell the groom in person but left a short note behind. Of course, since she's leaving him for the Designated Hero we never see any negative repercussions of this selfish act.
 * Subverted by The Wedding Singer, in which the bride who does this to her groom is in no way treated sympathetically, and her motives are revealed to be both shallow and, as her husband-to-be quite reasonably points out, nothing which couldn't have been raised the day before the wedding, thus sparing him some humiliation at least.

"Tala: [On her sister needing to call her husband and tell him what she is doing] That is exactly the kind of relationship I want to avoid. At all cost. Leyla: So your fiancée isn't like that? Tala: Hani? No. He is an Arab. Is born and brought up in Jordan. But he is different from the rest. Kind. Open minded. And he makes a great martini. Leyla: He sounds wonderful. Tala: Yeah. He is.... He is. At least I can't find anything wrong with him. Leyla: Why are you trying? [Pregnant pause while Tala stares into Leyla's eyes, before changing the subject.)"
 * Then, of course, there's The Graduate, which is not ignorant of the implications of the act. Not only is the ceremony already over by the time they do it, after the thrill of the act wears off they're left sitting apart from each other on a bus, both with looks on their faces that say "Did we really just do the right thing?"
 * And parodied to hell and back in The Simpsons, when Grandpa Simpson interrupts Grandma Bouvier's wedding to Mr. Burns in a similar way for similar reasons. Far from running off with Grandpa, Grandma takes this opportunity to say that she doesn't really want to marry either of them; Grandpa decides that this is good enough for him, grabs her and runs off with her anyway.
 * A mild subversion in Made Of Honour. After the would-be bride kisses the hero, the bride's mother smiles at her neighbour, overjoyed the heartwarming sight... only to have her smile falter as her neighbor, the understandably irked mother of the groom glares at her. In a further mild subversion the jilted groom, while accepting the wedding is off ends up punching the hero in the face, and is not exactly portrayed as being wrong in doing so.
 * Groom's Mother: * unintelligibly mangled due to accent* Hero: "What'd she say?" Groom:"She said I should deck you." Hero:"Oh." Groom:"She's right." * PUNCH*
 * In Saving Face, in something of a Shout-Out to The Graduate (staged in a similar manner), the heroine gets her pregnant mother to abandon the guy her grandfather had bullied her into marrying at the altar. The mother then ends up with the guy who fathered the baby, though he was pretty passive through the entire movie.
 * In Spaceballs, Princess Vespa does this to the uninspiring Prince Valium twice, once at the beginning of the movie, and once at the end when her true love Lone Starr crashes the wedding ceremony. Valium doesn't really seem to mind, though. Partially because he's a narcoleptic that has no dialog anyway, and partly because the only reason the two of them were getting married at all was because Valium and Vespa were the only Princess and Prince in the universe, respectively. Until Lone Starr finds out he's a prince too, thus fixing the problem.
 * The Frank Capra classic 1934 Screwball Comedy It Happened One Night: Claudette Colbert runs away from her wedding to a rich playboy in favor of Clark Gable's smart-mouthed freelance journalist--with her father's subtle encouragement (he had the getaway car ready). The movie does note that the scene is extremely embarrassing to said playboy when this is foreshadowed earlier in the film, at least acknowledging the effect on the groom (though also implying he deserved it in the same scene).
 * Frog, Sally Field's character in the Smokey and the Bandit trilogy, does this twice to Sheriff Justice's painfully incompetent son Junior. At the beginning of the first movie, she simply wants to get away from Junior; in the second movie, she runs away because Bandit is about to make a lucrative cargo run and Frog was offered a piece of the action by Snowman, the Bandit's partner.
 * Played with in the recent film The Proposal. After spending a weekend with the groom's family, the bride confessed at the altar to the whole family that she had blackmailed the man (her subordinate at the New York publishing firm where they both worked) into marrying her to avoid being deported. Of course after the tearful departure and as she was packing up her office the guy managed to catch up to her and propose for real.
 * Also played with in While You Were Sleeping - the bride waited until the wedding ceremony to confess that she had just pretended to be the fiancee so that she could be a creepy voyeur check in on the guy she had a crush on when a serious accident landed him in a coma. (Incidentally, Sandra Bullock played the bride in question for both this and The Proposal.) To be fair to her, this one at least tried to tell the family the real situation a few times before this but something always seemed to interrupt her.
 * The title character in Penelope becomes this, after a suitor proposes to her only to save his reputation, and she accepts only to break the curse. He is greatly relieved when she runs.
 * Tala in I Can't Think Straight is a serial Runaway Bride, having a history of dating whatever young successfull man that her parents would aprove of only to break it up once the wedding was up. At the start of the movie she is on fiancée nr. 4, and her relatives are placing bets whether she break it up before or after the engagement dinner. Turns out she has a really good reason for her behavior (It's all there in the title).

Literature

 * In some Robin Hood stories, Robin and his Merry Men stop a young maiden marrying some rich, old Norman scoundrel so she can be with her true love (often Alan-a-Dale). Of course, this was more justifiable when the Arranged Marriage was common.
 * In Robin of Sherwood, the groom was the Sheriff of Nottingham. Who made it quite clear he couldn't stand the girl, and was just interested in the dowry. When the Merry Men rescue her, but fail to steal the money, he's delighted.
 * Jane Eyre did this, though not without reason - technically, the wedding had already been canceled. All Rochester could offer her was
 * In Federico Garcia Lorca's Blood Wedding, the Bride runs away with her cousin's husband, AFTER she gets married to another man.
 * At the very end of Emily's Quest,
 * In the Sherlock Holmes story "The Adventure of the Noble Bachelor", the bride vanishes directly after the wedding. Everyone assumes she's met with foul play, but in fact she's run off with her previous husband, whom she had believed to be dead until he tracked her down the day of the ceremony.
 * In the first Sweet Valley High Saga book, Alice Robertson (the future mother of the twins) runs out on her fiance Hank Patman (the future father of Bruce), partly when she realizes at the last minute that she doesn't really love him and that they're not right for each other, but mostly because of her falling in Love At First Sight with Ned Wakefield (and according to the book, their ancestors have been trying to hook up for nearly 200 years).
 * In the last "Sisters Grimm" Book, 'The Council of Mirrors', Sabrina's wedding is crashed by Puck. Wouldn't apply, except that the epilogue shows that she and Puck now have two kids together. Ouch for her would-be husband, Bradley, whom we never hear of again.

Live Action TV

 * Played straight at the end of the seventh series of Frasier, in which Daphne abandons her groom at the altar to be with Niles; subverted in the next season in that, rather than running away, both Niles and Daphne elect to confess to their respective partners and face the music. The show also treats the occurrence in a somewhat realistic fashion, in which both Niles and Daphne have to contend with the bitter and spiteful (if pretty justified) reactions of their partners and insecurity in their relationship in the episodes that follow, rather than it being an automatic Happily Ever After for the two.
 * This happened to Frasier himself in Cheers, as Diane left him at the altar for Sam. You'd think, then, that he might have been a bit more disapproving of the above.
 * In Doctor Who, Amy Pond joins the Eleventh Doctor in the TARDIS the night before her wedding. At least in this case, she rationalizes that she can use the time machine to come back whenever she wants and not actually miss the date.
 * Shane in The L Word. After a reunion with her estranged father, who shares her womanizing tendencies, spooked her into thinking that if she went ahead with her wedding to Carmen and started a family, she'd eventually abandon them just like her father did to her, Shane decided that leaving her bride at the altar would be the lesser evil.
 * The very first episode of Will and Grace has Grace leave her groom because Will disapproved of him. We don't see the guy at the time, but we're told he treated her like dirt and Grace was only marrying him to avoid spinsterhood, so it seems justified, except for the question of why she waited so late to dump him.
 * Parodied in an episode of The King of Queens. Spence discovers his old girlfriend is getting married, realizes he still has feelings for her, so he and his friends have to drive over to the place the wedding is being held to tell her. After plenty of wacky events that delay them getting there, they get there just when the priest is giving the "if anyone objects to this union, let them speak now or forever hold their silence" line. Spence is about to step forward and object, when another guy in the audience stands up, declares his love for the bride, and she runs off with him instead.
 * In Friends Rachel ran away from a wedding. This was the first event in the series and the cause of many problems for her, so it's basically the 'setup' for Rachel's character. It was later revealed that her groom was already cheating on her and an alternate universe episode showed that had she actually married him, the marriage would have been miserable and eventually collapsed due to his infidelity.
 * Narrowly averted later on in the series, when Ross says the wrong name at the altar and his fiance finishes the ceremony before fleeing the reception and mailing the divorce papers to him.
 * Done twice in an episode of Monk: An man is found innocent of a murder Monk worked on, and Monk (feeling very guilty about putting an innocent man in jail) helps him get back together with his ex-girlfriend on her wedding day.
 * Despite obviously still having feelings for Hank, as even Bill's daughter points out, Californication's Karen goes through with the exchange of vows, only to run away with Hank at the after-wedding party.
 * In How I Met Your Mother He's mad at first, but then accepts her decision shortly after. The trope may count as a Deconstruction by showing how hard it was for Ted to go through that and how he carried it around afterwards. It was then parodied when a movie called "The Wedding Bride" was made about it that Flanderized Ted into a pantomime villain fiancée and   into a muscle bound Purity Sue.
 * Suddenly Susan starts when Susan (Brooke Shields) escapes from her wedding ceremony and even gets to rip her gown when she gets out of the church. Subverted when the only person who praises her for it is the groom's brother, who knew he would eventually make her miserable and relishes the humiliation he'll suffer.
 * In The Drew Carey Show, Drew marries Lily Crawford, but she jumps in the limo and drives off alone, with the explanation of "I can't do this."
 * In A Different World, Dwayne proposes to Whitley--as she's marrying another man. He's being dragged off by security guards, but still pleading with her to accept when she yells out "I DO!", then offers a lame apology to her groom before dashing down the aisle into Dwayne's arms.
 * Happens in the final episode of Sabrina the Teenage Witch when Sabrina dumps her sudden new love interest at the altar for her original love interest, Harvey.
 * Not quite--she examines her and her fiancé's "Soulstones," which don't fit together, meaning they're not actually soul mates. She tells her would-be groom that she's unsure about the wedding and the two agree to call it off. Once outside the church, though, she happens to see Harvey...and it turns out their soulstones fit.
 * Carol did it to Jodie on Soap. Justified because they were only getting married because she was pregnant, and she'd been expressing reservations from the beginning.
 * Done on an episode of Family Matters when a friend of Steve's is getting married. As the bride walks down the aisle, she encounters an ex, who happens to be the ceremony's piano player. He invites her to grab some coffee, and she happily accepts. Despite this being a comedy, for once, it's portrayed as an incredibly cruel and selfish think for her to do--her ditched would-be groom tries to throw himself off the roof of the church afterwards. Fortunately, the cop sent to talk him down happens to be an ex of his.
 * Seen frequently on Soap Operas, of course. Subverted in that often, the groom in question is a Jerkass, which ends up justifying the woman running out on him to reunite with her true love.
 * At the very beginning of the first episode of Happy Endings, Alex ditches her long-time boyfriend Dave at the altar and briefly runs off with another guy before going on their honeymoon alone. Subsequent episodes have dealt with them coming to terms with being Just Friends after having been a couple for so long.
 * In The Wanderer, the reincarnated Lady Claire literally leaves her present day fiancee at the altar for her similarly reincarnated Knight.
 * In Pan Am this is Laura's back story.
 * An unusual variant on McLeod's Daughters, where Jodi goes through with the ceremony but runs when it comes time to sign the marriage certificate.
 * In a few episodes of Kath and Kim Kel is described as having been jilted at the altar four times, always as a result of his supposed friend Sandy Freckle. Oddly, when we actually see flashbacks to his past fiances, in three cases there's little to indicate they actually got as far as the altar before Sandy moved in.

Music

 * Played with in Billy Bragg's "Mother of the Bride", in which the bride does not run away from her wedding, but the narrator of the song very much wishes she had... with him. Her mother concurs with him, for what it's worth.
 * Gilbert O'Sullivan's "Alone Again Naturally," the first three verses of which are a prolonged moan about getting dumped at the altar.

Newspaper Comics

 * This was part of Raven Sherman's back story in Terry and the Pirates. She ran around away from a society wedding, fleeing to China and setting up a medical mission.

Video Games

 * In Final Fantasy X, Yuna makes a daring escape by jumping off the skyscraper where the wedding is being held and summoning a flying aeon to catch her. In this case, the wedding wasn't for love in the slightest and both bride and groom had ulterior motives to the ceremony. Said tower dive happened when Yuna's intentions were revealed and the groom announced he was going to kill her friends.
 * In Dragon Quest VIII,
 * In Grandia, Feena dumps Pakon at the altar and runs off to go adventuring after Justin and Sue crash the wedding. Of course, given that 1) The engagement was only in Pakon's mind, 2) He had quite literally kidnapped her just before the wedding, and 3) She had spent the entire ceremony up to that point bound and gagged, her ditching the guy was entirely justified.

Western Animation

 * An episode of Jimmy Two-Shoes had the princess Beezy was arranged to marry run off at the last moment. Since the whole thing was a Shotgun Wedding anyway, no one minded.
 * In The Simpsons episode "Springfield Confidential", Skinner admits he does not want to marry Edna and the Simpsons have to work to keep him from leaving her at the altar. However, Edna finds out and chooses to dump him instead.
 * In the same episode she leaves Comic Book Guy at the altar. This was also justified, since this was a quickie (Klingon!) wedding after a short rebound relationship and she realized it wouldn't really work out.
 * In Lisa's Wedding, Lisa is told of her future relationship with Hugh Parkfield. Before the ceremony he expresses frustration with the rest of the Simpson family and slips that he really doesn't expect Lisa to ever see them after the wedding; Lisa, stunned, chooses to call everything off.
 * Avatar: The Last Airbender has this if you stretch it: Katara's grandmother Kanna ran off before an Arranged Marriage to a man she didn't love, moving to the Southern Tribe.
 * Didn't love? She marries the guy after 60 years apart after marrying someone else and having a family. She ran away because even though she loved Pakku, she didn't want to be forced to marry him.
 * In an episode of the Rugrats, Elaine is supposed to marry Ben, but she is nervous and hides out in the gardens. He reassures her (and reveals that he is nervous, too), and they actually get married.

Real Life

 * Jennifer Wilbanks, who had a complete nervous breakdown and ran out on her future husband before the wedding and then went missing, which caused the whole state to initiate a massive search for her that wound up costing in the tens of thousands of dollars. When she finally was found and she explained how she ran because of the pressure, people weren't too happy with her and she was forced to do many hours of community service (though this also had to do with her claiming she was kidnapped by a Hispanic man after she resurfaced).
 * Playboy head honcho Hugh Hefner had his third wedding fall apart less than a week before the ceremony as the bride cancelled the arrangements, saying simply that she "changed her mind".

Anime and Manga

 * In Pokémon, James of Team Rocket is engaged to a rich girl called Jessiebelle (who looks a lot like Jessie). She carries a whip and wants to turn James into a real gentleman by 'training' him.
 * In Rappi Rangai, every time Raizou has finished impressing a girl he wants to marry, he continues chickening out and running away while his bodyguards beg him to pop the question already. To be fair, the story would probably just end if he did.
 * In Hell Teacher Nube,.

Comics

 * In Invincible, the title hero doesn't go through with his marriage to a fish-queen-lady-thing. Instead of running, he pretends to be too scared to fight the monster to complete the ceremony.
 * In X-Men, Alex Summers/Havok breaks off his marriage to Lorna Dane/Polaris while she's walking down the aisle in order to be with another woman, Annie; since the writer, Chuck Austen, viewed Alex and Annie as stand-ins for himself and his wife, and had characterized Polaris as a violent psychopath, we were meant to root for him and not Polaris when she, naturally, went crazy and tried to kill the both of them.
 * Of course you're meant to support Havok, what kind of man wouldn't ditch the crazy chick suffering from post-traumatic stress at the altar to visit Paris with the woman who he dated while he was in a coma? That wasn't a typo; there was telepathy involved.
 * Lorna, for all her violent, Magneto-helmet-over-her-wedding-dress psycho-bitchiness, did raise the very valid point that he could have called things off before the ceremony.
 * Subverted in General Protection Fault..
 * In Scare Tactics, hillbilly werewolf Jake Ketchum ran away from a Shotgun Wedding to a ghoul, intended to unite their feuding clans.

Film

 * Four Weddings and a Funeral.
 * The protagonist of In & Out leaves his fiancée at the altar after finally coming out of his Transparent Closet.
 * Harold Fine (Peter Sellers) in 1968's I Love You, Alice B. Toklas! does this twice. The first time he's become enamored with another woman (Nancy, a hippie) during the wedding preparations. Amusingly, a minor subplot reveals the jilted bride, Joyce, basically gets over this. When Harold becomes disillusioned with Nancy and the hippie lifestyle at the end, he reconciles with Joyce and they attempt to wed again, but he gets cold feet at the altar once more (having realized he doesn't know what he really wants out of life). Joyce just says, "I knew it..."
 * The Olsen Mary-Kate & Ashley Olsen Film It Takes Two: he was marrying the Rich Bitch, so it's okay! They also make her suffer through a Humiliation Conga as she leaves the chapel.
 * Dennis, in Run Fatboy Run
 * Sex and the City: It wasn't her he was running away from, but rather the large, public, publicized, display he'd never been comfortable with in the first place.
 * Jake Blues in The Blues Brothers, somewhat played for laughs or suspense. He leaves his bride (played by Carrie Fisher) at the altar, she chases after Jake and Elwood throughout the picture with a machine gun, and finally
 * Danny in Just Go with It. The actual jilting happens off-screen, presumably because the would be bride was so likable and sweet natured Danny would come across as too much of a Jerkass to audience.
 * Apparently happened in the backstory between Captain Smollet and Benjamina Gunn (Kermit the Frog and Miss Piggy) in Muppet Treasure Island.
 * In Flubber, the protagonist doesn't run out on his fiancée, he just...kind of forgets to show up. Three times.

Literature

 * Landen Parke-Laine in The Eyre Affair - although this is more a case of Speak Now or Forever Hold Your Peace. And it's not even him who is the party in the wrong.
 * Easily the most famous case of this is Miss Havisham's runaway groom  in Great Expectations. He only got close to her to defraud her of her money and once he completed this, he sent her a letter informing her of the truth just short of the wedding and then beat town. Miss Havisham goes crazy and hates men for the rest of her life.
 * In The Yiddish Policemens Union,  bails on an Arranged Marriage and the entire ultra-Orthodox community he was born into and repressed by.
 * In Robert Asprin's fantasy novel Hit or Myth, King Roderick attempts to escape his arranged marriage to Queen Hemlock by foisting his job off on court magician Skeeve.

Live Action TV

 * In Buffy the Vampire Slayer, Xander dumps Anya at the altar, although that's just cold feet; there's no Other Woman involved.
 * There were exceptional circumstances, too: an old man claiming to be Xander himself from the future showed up, showing young Xander horrible visions implying he would kill Anya if the two of them got together (which merely augmented his fear from his parents' own unhappy marriage). It turns out, but by the time this comes out Xander is too freaked out to go through with it. Both Anya and Xander are depicted sympathetically.
 * Played a bit in an episode of Star Trek: The Next Generation. Here, Lwaxana Troi decides she doesn't want to get married to an old prude after all and to call the wedding off, she decides to attend the ceremony in the traditional Betazoid bridal costume--nothing. While the ceremony's witnesses, well aware of Troi's true intentions, watch this with amusement, the Groom is incoherently repelled and flees the ceremony.
 * In Grey's Anatomy, due to a Role Ending Misdemeanor, Preston Burke's last appearance was when he left Cristina at the altar.
 * Played with for extremely dark comedy on Peep Show; marrying someone he didn't love (but was too embarrassed to break up with), Mark ends up hiding in the vestry of the church until he's discovered, whereupon he (very very very) reluctantly goes through with the wedding (to the extent that he looks around hopefully at the Speak Now or Forever Hold Your Peace moment and -- along with Sophie, his bride -- bursts into tears when the vows are read. The wedding car doesn't even make it out of the church grounds before Sophie abandons Mark, screaming about how 'horrible' he is. The next season sees much discussion (and passionate defense on Mark's part) about whether what he did technically constitutes a 'jilting' or not, since he ended up marrying her anyway.
 * Dennis dumps Carol at the altar in Ed, because he knows she would rather be with Ed.
 * Eric in That '70s Show, realizing that he and Donna are not ready to be married. Later, Donna agrees with him.
 * ER: Carol's fiance dumps her on their wedding day after gently, but firmly getting her to admit she doesn't love him the way he loves her.
 * Played with when Chandler in Friends runs away on his wedding day, because of his commitment issues. His friends eventually persuade him to come back, before Monica would notice his absence.
 * A rare male example is mentioned in Midsomer Murders. DCI Barnaby managed to get through the important part of the ceremony, but ran off after saying, "I've got it!" instead of "I do" to chase a murderer. When his wife decides she wants to have a proper ceremony for their anniversary, he interrupts it by.
 * In the Doctor Who episode "The Wedding of River Song", we finally learn exactly why Queen Elizabeth I was so pissed at the Doctor way back in "The Shakespeare Code": they were supposed to elope, but he never showed.
 * Neighbours did this with Toadie and Stephanie (as a result of Toadie realizing that Steph was far less enthusiastic about it than he was), Marc and Stephanie (Marc had fallen in love with Steph's sister Flick) and Mark and Annalise (Mark suddenly decided to become a priest - ironically, he had only converted to Catholicism because he was marrying Annalise).

Urban Legends

 * An urban legend about the groom catching the bride cheating. He goes through with the wedding, up until he distributes a special gift to the guests - an 8x10 picture showing the unfaithfulness, while leaving the expenses for the bride's family. Example: http://www.truthorfiction.com/rumors/g/groomsrevenge.htm

Video Games

 * In The Legend of Zelda: Majora's Mask, Kafei is supposed to marry Anju on the day of the annual festival, but has run away. Justified, in that he's under a spell that's turned him into a child, and needs Link's help (doesn't everyone?) to get his proper body back.
 * In the manga based on the game,

Western Animation
"Once took a Texan to a wedding... He kept forgetting, his loneliness led him His thoughts turned to home and we turned..."
 * In Chip 'n Dale Rescue Rangers, Monty would have married Désirée D'Allure if he hadn't encountered that truck loaded with cheese.
 * In Dungeons and Dragons, Eric agrees to be married to a Queen, but when the ceremony includes listing a series of extremely dangerous trials the groom is supposed to do, he instantly makes his escape before the official even finishes. Well, that and she turned into a troll at the altar.
 * In El Tigre, Puma Loco (in his younger days) ran away with a woman named Dora, leaving Lady Gobbler at the altar.
 * does this to in the Futurama movie Bender's Big Score. Although, to be fair, he only did it
 * In The Fairly Odd Parents, Mark Chang runs out on Princess Mandie at the altar. But since this was an Arranged Marriage to an Ax Crazy princess that he never wanted anyway, it's portrayed as proper.
 * Implied in the song "Worthless" in The Brave Little Toaster, when the Texas limo tells its story:

Film

 * The climax of The Guru has a wedding broken up by two people - one who professes his love to the groom and the titular character declaring his love for the bride. Both are successful.
 * The conclusion of Mamma Mia! has the couple decide not to get married quite yet - mainly due to the fact that the whole wedding ceremony was an excuse for the bride to meet her real father (out of three possible men.) Segues into Why Waste a Wedding? when Donna and Sam get married instead.
 * The conclusion of the second Princess Diaries film, where both halves are marrying out of duty (she for her country, he for his parents). Neatly combined with No Sparks. They remain very good friends and end up dating other people at the end. Also segues into Why Waste a Wedding?, as Queen Clarisse and her Head of Security Joe get married instead after several decades of hiding their feelings.
 * Occurs in Ever After, with Prince Henry and the Spanish princess he was suppose to marry. Right at the alter, he realizes the reason why she was hysterically crying was because she was in love with someone else and didn't want to go through with the wedding, just like him. So he calls off the wedding and runs off to find Danielle, just as the princess runs into the arms of her beloved also.

Live Action TV

 * In Bones, Angela and Hodgins run away from their own wedding--together--after they discover  They leave behind a horrified, confused group of people, with Brennan (the maid of honor) and Booth (the best man) standing at the altar with the priest. Brennan clears her throat awkwardly and asks what they're supposed to do.
 * There was a Reality Show, don't remember which, where two couples who met over the course of the show were to be married, and both ended like this. In one couple, it was the bride who backed out; in the other, the groom. It was pretty much the death-knell for wedding-themed reality shows (as opposed to just dating), since they've never ended well. Who would have thought marrying someone you've only known for three months was actually a bad idea?
 * On Life Goes On, eldest daughter Paige, who has been having panic attacks in the days leading up to her wedding, waits until she's at the altar before asking her fiance if he really loves her. He admits that he does but that they're not right for each other and nowhere near ready. Sure enough, she goes dashing down the aisle to reunite with her true love, with her now ex-fiance's blessing.
 * Engineered by Tom in Waiting for God - Diana has been single for over 60 years and wants to remain that way, but her latter-years lover Tom is unsatisfied with his role as the last of a long line of equally significant lovers. After many hijinks as Diana tries to avoid having to marry Tom, Tom ultimately refuses to marry her instead. They then carry on their affair as normal, Tom accepting that Diana having been willing to marry him at all is good enough and he doesn't need to actually force the issue.
 * An episode of The A-Team takes this a step farther by having the eponymous team show up to rescue a bride from being coerced into marrying the Villain of the Week. Their escape plan involves having Murdock walk down the aisle disguised as the bride; thus resulting in Murdock becoming a runaway bride himself. Murdock later writes the villain a letter of apology for leaving him at the altar.