''Naughty Marietta'' is an operetta with music by Victor Herbert and libretto by Rida Johnson Young. It opened in October 1910 in Syracuse, New York, and was the TropeCodifier for American operettas.

The story is set in 1780 New Orleans, and focuses on American Captain Dick Warrington's attempt to capture the notorious pirate Bras Pique, as well as his developing relationship with the beautiful and spirited Neapolitan Countess Marietta D'Altena, who's come to New Orleans as a casquette girl to escape an ArrangedMarriage and to find the man who can complete her DreamMelody, as that's who it's foretold she'll marry. There's also romantic tension between Lizette, another casquette girl, and Silas, Captain Dick's and later French Lieutenant-Governor Grandet's servant (called Simon in the original premiere, then changed to Silas in other versions). It was made into a movie by MGM in 1935, starring Jeanette [=MacDonald=] as Marietta and Nelson Eddy as Warrington in their first collaboration.
!! This work contains examples of the following tropes:
* ArrangedMarriage: Marietta ran away to escape one in Naples.
* BetaCouple: Lizette and Silas/Simon.
* BeautifulSlaveGirl: Adah, Etienne Grandet (Lieutenant-Governor's son)'s quadroon slave mistress.
-->'''Etienne:'''(''at Quadroon Ball, where he's auctioning her'') "La Belle Adah, the most beautiful slave in New Orleans!"
* BilingualBonus: Doubles as a MeaningfulName. "Bras Pique" means "tattooed arm" in French. Etienne has "Bras Pique" tattooed- guess where? So do his pirate crew.
* BreakawayPopHit: 'Ah! Sweet Mystery of Life', the DreamMelody, is an older example, since ''Naughty Marietta'' was written in 1910.
* CorruptPolitician: Lieutenant-Governor Grandet.[[spoiler: His son, Etienne, is Bras Pique. And he's one of the only two people who know. His family uses whipping boys to take punishments for them. Silas gets appointed as the new whipping-boy midway through the operetta.]]
* DevilInPlainSight: No-one except his father and his slave mistress Adah has ''the slightest clue'' that [[spoiler: Etienne is really Bras Pique or that he wants to establish Louisiana as an independent nation, a dictatorship under his control]]
* DreamMelody: 'Ah! Sweet Mystery of Life' is the TropeNamer.
* IAmSong:
** The title song, where Marietta sings about how "there are two little maidens that live in my heart" and "when I'm good I'm very very good, but when I'm bad I'm horrid!"
** Also 'Tramp, Tramp, Tramp!' which introduces Captain Warrington and his band of soldiers and woodsmen.
* IJustWantToBeFree: When Adah is freed at the climax, she [[spoiler: exposes Etienne's secret]]
-->'''Adah''': I- a free woman? Then.. I must act like one-- Listen, Monsieur, you would prevent this marriage? \\
'''Dick''': If I could. \\
'''Adah''': On Etienne Grandet's right arm you will find his name! \\
'''Dick''': His name? \\
'''Adah''': Bras Pique!
* InNameOnly: The 1935 movie, which removed the stage characters of Adah and Etienne, eliminating the hunt for Bras Pique, and making Marietta French, among other changes. But then, YMMV.
* IWantSong: 'Neath The Southern Moon' for Adah, after she discovers that [[spoiler:Etienne has stopped loving her. He's paying attention to Marietta in the hope of getting her to marry him.]]
* KickTheDog: Marietta considers Etienne to be doing this when he tells her that he plans to sell Adah, who is genuinely in love with him.
* LampshadeHanging: On the poor quality of Marietta's disguise as a boy.
* MistakenForCheating: A variation- they weren't really a couple yet, but Marietta decides to accept Etienne's proposal when she thought Warrington was flirting with Adah.
* MixedAncestry: Adah.
* OfficialCouple: Warrington and Marietta.
* RealLifeWritesThePlot: Emma Trentini, the original Marietta, was an Italian opera diva with a heavy accent.
* RebelliousPrincess: Marietta is a non-royal version.
* RunawayFiance: Guess who?
* SlaveLiberation: At the Quadroon Ball, Warrington buys Adah to set her free.
* SweetPollyOliver: Marietta disguises herself as a boy to remain hidden from people looking for the Countess. Her disguise isn't very good.
* TheBigEasy
* TheIngenue: Coloratura soprano Marietta.
* VillainSong: 'You Marry A Marionette', sung by Etienne trying to convince Marietta to marry him.