Voiced by: Takuma Gōno (JP), Gabriel Damon (EN)
- Berserk Button: Don't make fun of his pajamas, and don't insult Icarus either.
- Beware the Nice Ones: He's a shy, easily scared and slightly immature kid, but when he gets serious....
- Curtains Match the Window: Brown hair and eyes.
- Disney Death: After he defeats the Nightmare King, Morpheus revives him.
- Sweet Tooth: He has a habit of sneaking late-night helpings of his mother's pies. Also, he was reluctant about going to Slumberland until Bon Bon presented him with a box of cookies from the Princess.
- The Hero
- It's All My Fault: He feels terrible that he broke his promise to King Morpheus which resulted in his capture, and even worse later on when Camille is captured as well after he failed to protect her in time.
- My God, What Have I Done?: He immediately feels the guilt over unlocking the forbidden door after witnessing King Morpheus being taken away.
- Pajama-Clad Hero: He does occasionally get the chance to change out of his pajamas, but just ends up back in them again at the start of each new dream.
- Took a Level in Badass
Voiced by: Hiroko Kasahara (JP), Laura Mooney (EN)
- Armor-Piercing Slap: She throws a punch hard enough to send Flip sprawling.
- Berserk Button: She is very vocal in her dislike of Flip.
- Beware the Nice Ones: She rarely gets angry but when she does...
- Flip is just that good at pissing her off.
- Cute Bruiser: Flip found this out the hard way.
- I Am Very British: In the English dub, she speaks with a posh British accent, which makes sense she is a princess, but it does waver a lot.
- Fiery Redhead: Downplayed in that she isn't normally angry, but when her temper does flare up, it's quite impressive.
- Lonely Rich Kid: The royal kind. Nemo was summoned to Slumberland in the first place to be a companion for her.
- Nice Girl
- Official Couple: Eventually with Nemo.
- Royal Brat: She shows shades of this when she first meets Nemo, but her brighter colors quickly come out when he tells her off for her attitude.
- Royals Who Actually Do Something: She accompanies Nemo, Flip, and the Professor to Nightmare Land to rescue her father.
- Tsundere: She starts off being harsh towards Nemo, but she gradually softens up a bit. However, she's still harsh towards Flip, not that he doesn't deserve it.
- The Ugly Guy's Hot Daughter: King Morpheus isn't exactly ugly, but his advanced age and girth combined with his jolly nature causes a visual dissonance between him and the pretty and petite Camille.
Voiced by: Kenji Utsumi (JP), Bernard Erhard (EN)
- Beware the Nice Ones
- Big Fun: He is a very large and jovial fellow.
- The Big Guy: How he can ride on his toy train with out crushing it is anyone's guess.
- Distressed Dude: The whole conflict involves him being abducted by the Nightmare King.
- The Good King: Oh so very much.
- Like a Son to Me: He quickly sees Nemo this way.
- Manchild: He has a huge playroom filled with toys.
Voiced by: Kōichi Kitamura (JP), René Auberjonois (EN)
- Hat of Authority: His tall stovepipe hat gives him an air of authority when he first appears.
- The Herald: Starts Nemo off on his journey by coming into his room to present Nemo with Camille's invitation.
- The Professor
- Not So Above It All: He's normally all about business and discipline, but when he gets on the dance floor...
Voiced by: Danny Mann (EN)
- Badass Adorable: He'll attack pretty much anyone or anything that tries to harm Nemo or his friends regardless of the risk.
- Ridiculously Cute Critter: Camille certainly thinks so.
- Sweet Tooth: He enjoys the Princess's cookies just as much as Nemo.
- Undying Loyalty: To Nemo.
Voiced by: Chikao Ōtsuka (JP), Mickey Rooney (EN)
- 0% Approval Rating: He's not well-liked in Slumberland. Considering his character, it's understandable.
- Cigar Chomper: Has an unhealthy cigar addiction.
- Dirty Coward: He'll do whatever he can to save his own ass in a sticky situation.
- Fun Personified: So he presents himself, although his idea of fun has little regard for consequences.
- It's All About Me: He's more concerned about himself than anyone else.
- Jerk with a Heart of Gold
- Never My Fault: He blames Nemo for opening the door containing the Nightmare King and denies having any involvement with it himself, despite being the one to talk Nemo into doing so in the first place.
- The Trickster: Resuming the role he had in the comics as a trouble-maker.
Voiced by: Sherry Lynn (EN)
- Ambiguous Gender
- Meaningful Name: See below.
- Nice Girl: She's very sweet and cheerful, fitting her name.
Oomp voiced by: Keiichi Nanba (JP), Alan Oppenheimer (EN)
Oompo voiced by: Masaharu Satō (JP), John Stephenson (EN)
Oompa voiced by: Hiroshi Ōtake (JP), Neil Ross (EN)
Oompe voiced by: Kōzō Shioya (JP), Sidney Miller (EN)
The Nightmare King
Voiced by: Tarō Ishida (JP), Bill Martin (EN)
- Big Bad
- Blob Monster: One of the forms he takes when released from the forbidden door is a giant mass of black goo, which he uses to capture King Morpheus and teleport to Nightmareland.
- Evil Overlord: He rules over Nightmareland, the Evil Counterpart of Slumberland.
- Evil Sounds Deep: And how.
- Knight of Cerebus: He wasn't in the original comics, which had no real antagonist to speak of outside Flip. And in the movie itself, the movie takes a much darker and more serious tone as soon as his existence is revealed to Nemo.
The String Ray
- The Dragon: To the Nightmare King.