Princesses Rule

"Even though the king and queen are totally dead, she still technically calls herself 'Princess'. How does that work? If you're the ruler of a nation, you're a fucking queen."

—The Nostalgia Critic, on the use of this trope in Felix the Cat: The Movie

As it says in Everything's Better with Princesses, occasionally in fiction, a princess is shown to be the absolute ruler of a realm, despite the fact that, logically, that would make her a queen. There could be a few reasons why she hasn't been crowned queen, such as the realm is explicitly a principality, they are waiting until the princess comes of age (although historically this doesn't usually happen), or the princess is only acting ruler, as regent for an incapacitated monarch. However, in fiction-land, this set-up doesn't usually even get a hand-wave. The ruler just is a princess for some inexplicable reason.

Note: Most ruling queens are technically princesses. That does not fit this trope. Nor does a queen referring to herself as a prince. Only a princess ruling as a princess counts.

Contrast God Save Us From the Queen. Compare Politically-Active Princess.

Examples of Princesses Rule include:

Anime and Manga

Gundam Seed Destiny: Princess Cagalli might count, though she prefers a different title, and she both averts and plays it straight in the series. Neither changes the fact that she's a princess and the highest official in her nation.
Princess Adina (Mokuba's virtual Opposite Gender Clone), ruler of Simlow in the virtual world in Yu-Gi-Oh!
In El-Hazard: The Magnificent World, Princesses Rune Venus and Fatora seem to be the co-rulers of Roshtaria (though it's uncertain how much political power Fatora holds).
In Magic Knight Rayearth, the Pillar of Cephiro is named Princess Emeraude. Curiously, her younger brother is Prince Ferio. So there may be something else in addition to being Pillar, like a royal family with titles.
Kirameki Project has the "acting ruler" version of the trope, with three princesses co-ruling. The eldest is also shown to be the Commander in Chief of the nation's armed forces.

Film

The Princess of Alamut from the Prince of Persia the Sands of Time film.
In the film version of Avatar: The Last Airbender the voiceover explicitly states that the Northern Water Tribe is ruled by a princess because her father was killed. In the original series her father, Chief Arnook, was alive and ruling himself.
Princess Oriana in Felix the Cat: The Movie (see page quote.)

Literature

Princess Ozma from the Oz books.
- Although there's no consistent title for the ruler of Oz, so this could actually mean that she's a princess as a fairy rather than a princess of Oz. We don't see enough of other fairies to be sure.
- Princess Langwidere from Ozma of Oz is a justified example, as she is only acting ruler until the return of the Royal Family.
Princess Jenna from the Septimus Heap series. She will, however, become queen. When the Time is Right.
Played with in the Wheel of Time when Elayne effectively rules Camelyn (the capital city) for several months as Daughter-Heir (the term princess exists, but is considered old-fashioned). This happens because there's a conflict over who should be Queen.
Gender-flipped with the lands of Emerald and Corisande in the Safehold series. The countries are ruled by their princes, however they are also specifically referred to as Princedoms, not kingdoms.
Princess Desmia in Palace of Mirrors, although she is a mere figurehead. By the end of the book, the kingdom is ruled by a council of thirteen princesses, all of whom have equal right to rule.
For some never explained reason the monarch of the Fomalhaut system in Edmund Hamilton's The Star Kings is 'Princess' Lianna.
In the later Black Company books, the Fantasy Counterpart Culture version of India is ruled by a prince. (At some point in the distant past, it was part of a now-defunct much larger empire.)

Live Action Television

This would seem to be the case with Princess Mithian from Merlin. She arrives in Camelot for an Arranged Marriage to King Arthur, with no sign or mention of her parents. When Arthur breaks off the engagement because he's still in love with Guinevere, he gives her full rights to the lands that were in dispute between their kingdoms, at which point Mithian says: "I would give up my own kingdom to be so loved." Presumably, she's the ruler of her own kingdom, but is still refered to as a princess.

Theatre

The male variation of this trope is featured in Emilia Galotti by Gotthold Ephraim Lessing. The antagonist, Prince Hettore Gonzaga is the king and regent of Guastalla in all but the title. Lessing probably did that to avert any obvious parallels to the regents of his time (the piece, albeit set in renaissance Italy, was a warily subtle commentary on the corrupted politics of the then-contemporary 18th century German states).

Video Games

Princess Peach in many of the Mario games. The original game referred to her as the daughter of the Mushroom King, but the games never mention him again after that.
Princess Zelda in some, but not all Zelda games and adaptations, notably Twilight Princess, where, apparently, she was about to be crowned queen before everything started going to hell. The Brawl manual also refers to her as "queen", for what it is worth.
- Which makes Midna, the titular The Legend of Zelda Twilight Princess an example as well.
- Other instances of Zelda don't have her rule anything, particularly The Legend of Zelda the Wind Waker. There she's just the descendant of an earlier Princess Zelda and what would be her kingdom is frozen in time beneath the seas. She doesn't actually become any sort of monarch until after The Legend of Zelda Phantom Hourglass.
  - The Legend of Zelda Skyward Sword also deserves mention, as Zelda in that game is a normal girl attending school with Link...although she is the headmaster's daughter, there is no royalty to speak of in Skyloft.
Princess Gutrune of Etrian Odyssey III: The Drowned City. In her case, it's stated by locals that the Senatus is seen as holding all the real power, particularly Senator Flowdia, while Gutrune is seen as a pretty figurehead.
The hierarcy of the Aristocrat Club in Rule of Rose ends in the Rose Princess, which is justified considering that these are young girls playing a long-winded game - obviously Princess sounds better to them than a Queen.
Due to her fathers insanity, Hilde is this for her nation in Soul Calibur IV. She's technically regent, however, not the monarch.
Imperial Princess Arlier, the leader of the Tiamat race in Knights in The Nightmare.
Discussed in Yggdra Union. Princess Yggdra is the de facto leader of her nation throughout the game, as her parents were both killed in battle with Gulcasa before the narrative actually begins. In all the excitement of getting her throne back (and then rescuing her from the aftereffects of a momentary Idiot Ball catch), there just hasn't been time for her to be crowned, and when this is brought up even Yggdra herself is rather nonplussed about it. She officially becomes Queen a little bit later, but personally refuses to accept the title until the war is over—probably for the same inexplicable reasons listed above.
|Soleanna is a duchy, and Princess Elise's father is referred to as the Duke of Soleanna. Elise, despite being the ruling monarch, is referred to as Duchess precisely once. In the Japanese dialogue.

Western Animation

Princess Bubblegum from Adventure Time.
- Most of the other princesses seem to be this way, too (as we see a huge gathering of them discussing political matters), though Lumpy Space Princess seems to be an exception.
Princess Starglo from Care Bears: Share Bear Shines is described as "the mother of all stars," yet is only a princess for some reason.
Princess Celestia and maybe Princess Luna from My Little Pony Friendship Is Magic are the rulers of Equestria (the first by day, the second by night), with no attempt to lampshade Equestria as a principality. (Word of God says this is due to Executive Meddling: little girls think princesses are good but queens are evil.)
Princess Berrykin from Strawberry Shortcake's Berry Bitty Adventures.
Princess Candy from Dave the Barbarian is ruling Udrogoth until her parents come back from destroying all the evil in the world.
Played with in Captain N. Princess Lana is the only ruler in Videoland, but her father is still alive, he's just trapped in another dimension.
Similarly, Princess Sally from the Sonic the Hedgehog series would be ruler if Robotnik hadn't taken over. Instead, she leads the resistance movement.
In Mickey, Donald, Goofy: The Three Musketeers, Minnie is cast in the role of Princess Minnie. Despite this, she's pretty much queen in every other aspect.
Despite the heavy use of Everything's Better with Princesses, this trope is averted by the Disney Princesses, as none of them are actually in a ruling capacity, except for Kida, who appropriately becomes a queen at the end of her film. However, the franchise may have contributed to the trope's perpetuation, through films like Snow White and The Seven Dwarfs that could cause one to perceive queens as "evil", and princesses as "good".

Real Life

This could become the case for Wales, which is a principality.^{[please verify]} Should the future heir apparent of the United Kingdom (the traditional ruler of Wales) be a girl then they will officially be the "Princess Of Wales" (note that Diana wasn't an example, since she was princess by virtue of being married to the Prince of Wales rather that actually holding authority).