A fashion choice in which a woman wears a skirt (or dress) over a pair of pants or shorts.
In Anime, it's common for some girls to wear bike shorts under their skirts, the characterization usually being one of shyness or tomboyishness (athletes are popular users of this trope). See also Modesty Shorts, for when a girl wears shorts under her miniskirt to avoid Panty Shots, and Tights Under Shorts, the sister trope to this.
It's also a very common outfitting choice in Kid Com shows, as well as for Adorkable female characters.
Note that this is applicable only when either the skirt or the pants could be done away with completely without making the outfit too risqué. Oddly enough some shows will still grant the wearer a Magic Skirt even though there's no panties to see.
Often seen in Real Life.
Sakura is an example for both variants. Before the Time Skip, she wears tight shorts underneath a quipao-like dress, afterwards she keeps the shorts and wears them with a short skirt and a sleeveless zipper vest.
The standard attire for Sound ninja follows a similar design as Sakura's first outfit. The top is a long tunic that falls to mid-thigh with a split on the sides, worn over either slacks or shorts.
Chihaya in the first five minutes of Chihayafuru when she is tacking a karuta club flyer to the bulletin board. Miyauchi-sensei was not pleased.
In Sangatsu no Lion, Hinata Kawamoto's casual wardrobe mainly consists of dresses over jeans.
Part of Android 18's signature outfit from Dragon Ball Z is a skirt worn over a pair of jeans.
Mekakucity Actors: Takane Enomoto◊/Heaphone Actor/Ene wears tight black shorts to mid-thigh beneath her plaid skirt. Hiyori also wears similar shorts beneath her pink dress.
In Xam'd: Lost Memories, Yunbo, the Team Mom on the Zanbani postal ship, wears what appears to be a long skirt over a collared work shirt, pants, and work boots.
In Supergirl: Cosmic Adventures in the 8th Grade, Supergirl wears a pleated red skirt over her Supergirl outfit (which is otherwise identical in design to Superman's usual costume). She was drawn with shorts under her skirt in the regular comics as well before her costume changed with the universe reboot in 2011.
Misfit, the teen member of the Birds of Prey, usually wears knee-length bike shorts under her short skirt, probably for the same reasons as Supergirl, above.
Shugo Kino in Pretty Cure Heavy Metal already wears her gym shorts (which actually resemble shorts) under her uniform whenever she goes to school at Isuten Junior High, but this trope is a LOT more obvious in the colder months, where she wears blue jeans under her uniform instead (as seen in later season 1 episodes), which allows for a non-Fanservicy variation of Dress Hits Floor in one scene in episode 41.
Films — Animation
In Hoodwinked, Red Puckett's outfit is a white shirt, a red-hooded cloak, and a blue skirt worn over blue jeans. She eschews the skirt entirely in the sequel.
MK's attire throughout Epic is a skirt over leggings paired with a pink hoodie.
As well as Human!DJ Pon-3 with tight pants, as seen in the Rainbow Rocks shorts.
Films — Live-Action
The heroine of Juno wears this on her poster, and a few times throughout the movie. At one point, she takes off the skirt when she goes to see Paulie, which Word of God says he knows her well enough to give her a hard time about.
In Sky High the GF of the main character wears a flower print skirt over jeans.
In Hidalgo, Jazira wears a long tunic over pants, a very common outfit for Arab women during that time period.
Kick-Ass. Hit Girl wears a pleated schoolgirl skirt over her purple superhero jumpsuit.
Cirque du Soleil: Worlds Away: Mia wears knee-length pants under her dress, most apparent during the finale when she spins and her dress flares out.
Averted in Austin & Ally. Ally wears dresses or skirts on their own, often achieving various high grades of Zettai Ryouiki. The few times she wears pants or shorts she doesn't match them with skirts. Trish averts the trope despite using layering of long t-shirts to achieve a similar but not as pronounced effect to what it would be if she were wearing actual skirts as per the trope.
Tosh does this in an episode of Torchwood because she wants to dress up to impress someone, but it's also really cold out.
Natalie wears a tan skirt over black pants (Though, her sprite and official art makes it hard to tell if the skirt isn't actually a waist apron).
A favorite for female player characters; PonyJill (''Another Wonderful Life'', ''DS Cute'') wears a skirt over pants, and Angela (Tree of Tranquility), and Molly (Animal Parade) wear visible shorts under their skirts.
Chie Satonaka from Persona 4 wears cycling shorts underneath her skirt. She doesn't ride a bike, so much as she needs them to cover up while fighting: she's particularly fond of roundhouse kicks.
The ending of Magical Girl Lyrical Nanoha A's Portable: The Gears of Destiny shows that Amita's non-fighting outfit is a Wild West inspired blue dress worn over thick pants tucked into a pair of boots.
This was sometimes used as a form of rebellion in the days when school Dress Codes required girls to wear skirts to class.
Often adopted as a practical solution in the winter months, by girls or women who want to wear skirts but don't want their legs to freeze off when they're walking around outdoors. The pants or jeans may or may not be discarded once they're inside.
The Churidar and Salwar Kameez are "default" versions of this trope; they retain the appearance and the practicality of the skirt-over-slacks theme, but are not usually worn without the pants, because the tops have two cuts on either side, going up to the waist. This actually serves two purposes: one, it gives more freedom of movement, and two: it looks pretty stylish.
They're also practical in the Middle Eastern and South Asian countries where they're primarily worn; skin covering is essential to prevent sunburn, but the outfit also has to be loose to allow air to circulate.
One early Feminist who tried the style gave it up; according to her every time she gave a speech on women's rights to a male audience they were so busy staring at her ankles they didn't hear a word she said.
Girls in Modern Orthodox Jewish communities often wear skirts over jeans.
This is common among Muslim women who feel (or are forcefullyinstructed) that "modest clothing" necessarily involves wearing long, loose, flowing garments—in public, at least. Such women often wear more fashionable outfits—often including slacks or jeans—under the loose garment, which would be taken off at home or in female-only settings.
Quite apart from any cultural reason, this was a favourite look of Trinny Woodall of What Not to Wear fame... and one of the few that never did creep into the mainstream of the UK for much of the 2000s. T&S got their way about A-line skirts, wedge heels, stretch-sided knee-boots and fitted tshirts. This one, assigned usually to tall or short-legged women never convinced anyone.
At least in Germany, this was part of women's fashion around the millennium. The twist: It was one piece of clothing, a pair of long pants with a micro-miniskirt in the same color sewn on.
Male example: Toshiya, bassist of Visual Kei band Dir En Grey, has been known to sport a skirt over his jeans.
Another male example: Kanye West has been known to sport a leather skirt/kilt over jeans, debuting the look in his Watch The Throne Tour with Jay-Z.