A musical comedy that parodies the well-known story of "Literature/ThePrincessAndThePea", ''Once Upon a Mattress'' started as a Broadway play, then later appeared as a TV special (more than once). It premiered in 1959, with music by Mary Rodgers, lyrics by Marshall Barer, and book by Jay Thompson, Dean Fuller, and Marshall Barer. As TheOtherWiki states, it's a popular choice for high school and community theater shows.

Its most prominent claim to fame is that it was the breakout role for actress CarolBurnett, who played Princess Winifred on Broadway, and appeared in several TV versions of the musical (first playing the princess, and then switched to playing the Queen as she got older). One Broadway revival featured Sarah Jessica Parker in the role. Tracey Ullman played her in the most recent TV film, which premiered on ''[[Series/WaltDisneyPresents The Wonderful World of Disney]]'' in 2005.

A royal minstrel reveals to the audience that the princess and pea story they've all heard (and is recreated as an OpeningBallet) wasn't exactly what happened -- he was there and has firsthand knowledge of the truth. Queen Aggravain (whose husband King Sextimus was rendered virtually powerless after he rendered mute by a curse) was determined never to let her son Prince Dauntless the Drab marry, so she was constantly creating impossible tests for prospective princesses to pass before they could have his hand. To make matters worse, ''no one'' in the kindgom was allowed to wed until he was. Sir Harry, alas, had just learned that he and his sweetheart Lady Larken were expecting a child, so he headed out to find a princess who hadn't yet gone through the tests. He brought back the feisty swamp Princess Winifred the Wobegone -- "Fred" for short -- who instantly won Dauntless's heart. Now the evil Queen had to come up with an impossible test...

!!Tropes featured in this work include:
* BetaCouple: Sir Harry and Lady Larken.
* BigShutUp: [[spoiler:Dauntless does this to his mother at the end after Winifred passes the sensitivity test, resulting in her being silenced and breaking the curse on King Sextimus.]]
* CurseEscapeClause: King Sextimus the Silent is destined to be mute until the "mouse devours the hawk".
* CutSong: "Very Soft Shoes" is cut from the television and film versions because it is a SuperfluousSolo. It's a singing and dancing number for the Jester that imparts some unnecessary background info on him, and it's done so late in the show that it conspicuously stops the plot.
* EverythingsBetterWithPrincesses: It's in the title. [[CaptainObvious Duh.]]
* FracturedFairyTale and TwiceToldTale: One of the earlier examples of the former.
* GenderBlenderName[=/=]TomboyishName: Princess Winnifred is known to her friends as Fred.
* GettingCrapPastTheRadar: Several in "An Opening for a Princess", while the court is bemoaning the WedlockBlock:
** "None of the ladies are having any fun"
** "No one is getting any... younger"
* HenpeckedHusband: King Sextimus (actually, he's more [[spoiler: hawk]]-pecked).
* HypocriticalHumor: You can say it almost relies on it.
** [softly] "I've... always... been... [belted, full-out] '''SHYYYYYYYYYYYYYYY''', I confess it, I'm '''SHYYYYYYYYY!!!'''"
** In the opening of Act Two, the Queen wants quiet for Princess Winifred and her sensitivity test, and she will get it even if she has to [[NoIndoorVoice SCREAM THE PALACE DOWN.]] "She's ordered twenty mattresses, the softest and the best, and she's threatened execution if we dare disturb the rest of her very special guest, she's ordered '''QUIET! QUIET! QUIET!'''"
* IAmSong: "Shy".
* IWantSong: "HappilyEverAfter".
* TheMagnificent: Parodied, with Winnifred the Woebegone, Dauntless the Drab, and Sextimus the Silent.
* MeaningfulName: Queen Aggravain (a portmanteau of "aggravating" and "migraine", and there's "vain" in there too as a bonus).
** And for a bit of a GeniusBonus, it looks similar to real mythological names like Ygraine, the mother of King Arthur.
** It's also a member of King Arthur's court, a sibling of Gawaine's. A male sibling, that is.
* MidwordRhyme: "In A Little While".
* MistakenForServant: Larken briefly mistakes Fred for a chambermaid. Although, to be fair, Fred was on her hands and knees wiping the floor (she had accidentally broken a vase) at the time.
* MommasBoy: Prince Dauntless.
* MyBelovedSmother: Queen Aggravaine.
** [[IncrediblyLamePun Not to be confused with]] My Beloved [[HeyItsThatGuy Tom Smothers]] as Sextimus in one of the TV versions!
* OpeningBallet: "Many Moons Ago" has the Minstrel presenting the original "Princess and the Pea" story in song, while dancers reenact it behind him. Crucially, the personalities and appearances of the King, Queen, Prince, and '''especially''' Princess are completely different from their counterparts in the rest of the show.
* PimpedOutDress: Queen Aggravain's wardrobe consists of dresses that are cut and decorated in outlandish ways. The princess in the story wear fancy dresses, but in proper styles.
* PlaceboEurekaMoment: How the Queen comes up with the idea for the mattress test. She asks the wizard to help her think of a test to give Princess Winnifred, but ends up just complaining without letting him get a word in edgewise. She ends up coming up with the idea all on her own, but still calls the wizard "a genius" for it.
* PluckyGirl: Princess Winnifred. She's so determined to meet the prince that she swims the moat to get to the castle faster!
* PropheciesRhymeAllTheTime:
** "Throughout the land no one may wed / 'Til Dauntless shares his wedding bed."
** "King Sextimus shall never talk / Until the mouse devours the hawk."
* [[spoiler: ShaggyDogStory: The subplot with Sir Harry and Lady Larkin. They go through a lot of trouble to find out what the test is, and make sure that the princess passes it. In the end, it turns out that she would've passed it without them.]]
* ShotgunWedding
* StraightMan: Queen Aggravaine, to virtually every other character's ridiculous shenanigans.
* TheTalk: Has its own musical number; unique in that the King can't speak, and has to do the whole thing in pantomime.
* TruckDriversGearChange: "Song of Love" is full of them.
* TomboyAndGirlyGirl: Fred and Larken, respectively.
* VillainSong: "Sensitivity" certainly has the feel of a villain song.
* WasntThatFun: At the end of the Spanish Panic, all the dancers but Fred have collapsed:
-->'''Queen:''' Are you feeling a little weary, dear?
-->'''Fred:''' No, let's do it again!
* WedlockBlock: Nobody is allowed to marry until Dauntless does.