The Wonder Pets (and Ollie)
- Accessory-Wearing Cartoon Animal: They all wear hats (a baseball cap for Linny, an aviatrix's hat for Ming-Ming, and a sailor's hat for Tuck) and when they're doing hero work, they wear capes too.
- Action Girl: Downplayed for Linny and Ming-Ming. They sometimes just save animals from inconvenient situations (like a dog who has to pee but is stuck in the house, or a bird with a bucket stuck on her head) but have also saved animals from actual danger (such as a beached whale and a penguin caught on an iceberg).
- Badass Adorable: They are cute pets, who travel around the world saving animals.
- Beauty, Brains, and Brawn: While not exactly, Tuck likes making things beautiful, Linny has the brains, and Ming-Ming has a brawn attitude.
- Chromatic Arrangement: Linny is blue, Tuck is red, Ming-Ming is green.
- Color-Coded Characters: Linny wears blue, Tuck wears red, Ming-Ming wears green.
- Free-Range Children: None of their parents have ever been shown, except for Ollie's mother. Justified in that they're pets, however, it's unclear whether Linny and Tuck are actually kids.
- The Hero: All of them.
- 100% Heroism Rating: Everyone loves them, especially shown in the episode "Save the Wonder Pets and "A Job Well Done!"
- Kid Hero: They're superheroes, and with the exception of Linny, they're children.
- Land, Sea, Sky: Linny representing land, Tuck representing sea, Ming-Ming representing sky.
- Gender-Equal Ensemble: Two girls (Linny, Ming-Ming) and two boys (Tuck, Ollie).
- Superheroes Wear Capes: They all wear capes.
- Superhero Team Uniform: They wear color-coded capes with their logo on it.
- Nice Mean And In Between: Tuck being nice, Ming-Ming being mean, and Linny inbetween.
- Not Allowed to Grow Up: They don't seem to get older after three years.
- Tomboy and Girly Girl: Linny is the adventurous and active tomboy to Ming-Ming's also active but more fashionable girly girl.
- Trademark Favourite Food: They always eat celery after saving the day.
- Two Girls and a Guy: The main trio.
- Voiced by: Sofie Zamchick
Linny the Guinea Pig is the group's leader. Linny is the brains of the outfit, a fearless guinea pig who will do anything to help a fellow creature in need. She represents the developmental age of a five-year-old and is also the oldest of the Wonder Pets. Linny reminds her fellow creatures to value teamwork and trust. Her favorite food is celery.
- Aside Glance: Linny always gives a wink to the audience at the end of each story.
- Blue Is Heroic: The leader of the team who wears a blue cape.
- Character Catchphrase:
- "This calls for some celery!" which she says at the end of every successful mission.
- She also says, "Good eye, Tuck!" when he observes something.
- Color-Coded Characters: Her cape is blue to set her apart from the others.
- Celebrity Crush: In "Save the Beetles!" she faints when The Beetles sing their song at the Octopus Garden.
- Death Glare: Linny gives Ming-Ming the stink eye when, in "Save the Visitor!", Ming-Ming suggests of the Visitor, "Maybe he's a guinea pig. He sure eats like one." (Linny is a guinea pig.)
- Deus Exit Machina: Linny ends up getting sick in “Save The Mouse” just to have Tuck and Ming-Ming save the mouse without her guidance.
- Early-Bird Cameo: She appeared in two shorts before the actual show premiered: Linny the Guinea Pig Under the Ocean and Linny the Guinea Pig In Space. These were included as bonus features on a Dora the Explorer DVD.
- I Am Not Weasel: Sometimes, a student or Ollie refers to her as simply "pig," or some other type of rodent, such as "hamster."
- Iconic Item: Her orange baseball cap.
- Incoming Ham: Linny in "Save The Puppy". "It's a puppy, he has to pee-pee, but he CAAAAAAN'T, 'cause he's stuck in the house!"
- The Leader: She's the leader of the Wonder Pets.
- Masculine Girl, Feminine Boy: Linny's tomboyish Masculine Girl to Tuck's Feminine Boy.
- Nice Girl: Linny is a very sweet guinea pig that makes sure others get along and tries to get her teammates to work together.
- Perpetual Smiler: She's pretty much always smiling, even in the face of danger.
- Sick Episode: She spends "Save the Mouse" sick with what seems to be some kind of cold or sinus infection.
- The Smart Girl: She's the smartest of the team.
- Rhyming Names: *Linny* the *Guinea* Pig.
- The Stoic: She almost always manages to remain unflappable no matter how badly her teammates might behave, particularly Ming-Ming. Also, you gotta give her some credit for being the only one of the team that didn't freak out when they first met The Visitor.
- Tomboy: Linny is very tomboyish and adventurous.
- Tomboy and Girly Girl: Linny's Tomboy to Ming-Ming's Girly Girl.
- Tomboy with a Girly Streak: Linny is definitely more tomboyish than Ming-Ming, but she doesn't mind dressing up from time to time for special occassions.
- Womanchild: Downplayed. She's said to represent the developmental age of a five-year-old despite being a full-grown guinea pig, however, she's actually quite sensible.
- Voiced by: Teala Dunn
Turtle Tuck is a very sensitive young turtle. He is the heart of the group and he has a deep emotional connection to all living things. Tuck loves to give and receive hugs. Developmentally, Tuck is a four-year-old. He is the least physically advanced of the Wonder Pets. He is, however, an excellent swimmer and demonstrates keen observational skills while out on their adventures.
- Always Someone Better: Feels this way about his cousin Buck.
- Color-Coded Characters: Wears red in contrast to the other two.
- Cuddle Bug: Loves to initiate group hugs.
- The Dandy: He loves to dress up like the others.
- Distressed Dude: "Save the Turtle!" involves him needing to be saved after his leg gets stuck in a coral reef in the Caribbean.
- Four-Temperament Ensemble: The Melancholic.
- Masculine Girl, Feminine Boy: The Feminine Boy to Linny's Masculine Girl.
- The Lancer: Sometimes serves as Linny's sidekick.
- Mad Libs Catchphrase: "Can I have a hug, [animal's name]?"
- Iconic Item: His sailor cap and aqua socks.
- In Touch with His Feminine Side: Loves to play with dolls and make things look pretty, he also loves hugging. However, in one episode, he was ashamed of playing with a pink car instead of a blue one.
- One of the Girls: Being the only male in the group.
- Phrase Catcher: Whenever he makes an observation, Linny will tell him, "Good eye, Tuck!"
- Red Is Heroic: The second-in-command of the team wears a red cape.
- Sensitive Guy and Manly Man: The Sensitive Guy to Ollie's Manly Man.
- Shrinking Violet: He's soft-spoken and gets shy sometimes.
- Semiaquatic Species Sailor: Is a turtle who wears a sailors cap.
- Voiced by: Danica Lee
Ming-Ming Duckling is outgoing and confident. She has recently learned to fly, and she loves flying more than anything, even though she can only get about 4 or 5 feet off the ground. Ming-Ming enjoys being the center of attention, can sometimes be overzealous, and often gets ahead of herself, which provides comedy in the show. Ming-Ming represents the developmental age of a three-year-old.
- Artistic License – Biology: She can fly (albeit not very well) despite not having grown any flight feathers yet.
- Celeb Crush: She has a huge crush on a Ringo Starr parody.
- Character Catchphrase: She says "This is sewious!" whenever she hears about an animal in trouble.
- Color-Coded Characters: Wears green to set herself apart from the others.
- Damsel in Distress:
- "Save the Duckling!" involves her needing to be saved getting stuck on top of the schoolhouse roof
- "Save the Dancing Duck!" involves her once again needing to be saved after she tries on some dancing shoes that make her not want to stop dancing.
- Girly Girl with a Tomboy Streak: Ming-Ming is definitely the more girly one in comparison to Linny, due to her being into more fashion. However, Ming-Ming can be as active and adventurous as Linny, and she wears a pilot's cap.
- Iconic Item: Her pilot cap and goggles.
- Jerk with a Heart of Gold: Downplayed for the "jerk" part; she's a bit of a showoff and has a bit of a smart mouth, but for the most part she's very sweet and loyal.
- Elmuh Fudd Syndwome: She says serious (and other words with "R"s) with a w.
- Little Miss Snarker: She's a baby duckling with a tendency to snark.
- Large Ham: She's a very dramatic kid, describing situations as serious when they aren't really.
- Rhyming Names: *Ming-Ming* Duck*ling*
- Tomboy and Girly Girl: Ming-Ming's Girly Girl to Linny's Tomboy.
- Attention Whore: Shown in the episode "Here's Ollie".
- Character Catchphrase: "Ollie, Ollie, Ollie to the rescue!"
- Character Tic: He taps his foot when annoyed.
- Forgetful Jones: Usually forgets what they're doing.
- I Just Want to Have Friends: He wants the Wonder Pets to like him and accept him.
- I Just Want to Be Loved: This is how he turns out to be. He just wants to be accepted by others, including the Wonder Pets.
- Iconic Item: His knight helmet.
- Innocently Insensitive: It's unknown whether he calls Linny a "pig" on purpose or not.
- Jerk with a Heart of Gold: He's actually not a jerk, but he does appear to want attention from the other Wonder Pets because he wants to be a hero just like them, and he actually tries to help them in some episodes.
- Sensitive Guy and Manly Man: The Manly Man to Tuck's Sensitive Guy.
Wonder Pets' Family Members
- Rhyming Names: *Ginny* the *Guinea* Pig
- Rhyming Names: *Winnie* the *Guinea* Pig