The human hosts
Blue's owner before he left for college. Blue's Clues & You! reveals that he now runs the Blueprints Detective Agency.
- Badass Longcoat: As per typical dress for his profession, he wears a very slick beige trenchcoat after becoming a detective.
- Breaking the Fourth Wall: He talks to the viewers, to be expected from a kid's show host.
- Cloudcuckoolander: Sometimes has trouble hearing the viewers and/or asks very obvious questions, as well as a tendency to make bizarre guesses to the game's solution in the earlier episodes (For example, in "What Time is It For Blue?", when he has all three clues that indicate that it's Blue's nap time, he thinks it's time for her to wrap a pillow in a blanket and read it a story), but is not stupid. He also wants to get a degree in hopscotch.
- Despair Event Horizon: He ends up suffering from this in Blue's Big Musical Movie over his failed attempts to find the clues before the viewers. Luckily, he eventually finds the last one first.
- Exploiting the Fourth Wall: Sometimes he asks the viewers for "help".
- Inexplicably Awesome: Blue can skiddoo, he can too... we don't know how, though.
- Keet: He is very upbeat and energetic.
- Limited Wardrobe: Always wears a green striped shirt and brown pants.
- Nice Hat: Wears a fedora to go with his private detective look (and also to hide his balding head)
- Private Detective: Blue's Clues & You! reveals that he now runs a detective agency.
- Running Gag: Generally, when viewers first find a clue, hell tend to confuse it with virtually any word that rhymes with clue. He even points out one time where he doesnt do this. (To be fair, Joe also did this, but not nearly as frequently.)
- Shaking the Rump: During the mail song, he shakes his bottom, pretending that he has a tail and is wagging it.
- Took a Level in Badass: Seems that playing Blue's Clues was pretty good investigative field training, since, after he graduated college, he opened his own Detective Agency by the time Blue's Clues & You! takes place.
Steve's younger brother. Blue's Clues & You! reveals that he works at the Present Store.
- Cloudcuckoolander: Like Steve, he has trouble hearing the viewers.
- Consistent Clothing Style: Joe wears different shirts but they always have a pattern of three squares on them.
- Inexplicably Awesome: Just like Steve and Blue, we don't know how he can "skiddoo".
- Keet: Is just as enthusiastic as Steve.
- Limited Wardrobe: Wore a shirt with squares on a horizontal line and brown pants. By Blue's Clues & You! the boxes are now presents.
- Suspiciously Similar Substitute: He and Steve are pretty similar in how they behave.
- Unlimited Wardrobe: Wears a different color shirt every episode.
Steve and Joe's cousin, and Blue's current owner.
- Affirmative Action Legacy: Contrasting his two white predecessors, Josh is Filipino.
- Blue Is Heroic: Blue is his theme color.
- Hollywood Genetics: Handwaved. The only explanation given as to how Steve and Joe are related to a Filipino is that he's their cousin, and even that raises a few questions.
- Keet: He's been shown to be very giddy and excitable. His introduction episode alone had him awe after skidooing for the first time, and him in shock over getting to sing "Mailtime" (in which he reacts with "I can't believe I get to sing this song"). His voice also gets rather squeaky when he gets excited. Possibly his most infamous example of this is in "Playdate with Magenta", where his reaction to being the first clue is even more over-the-top than when it happened to Steve. He goes complete Motor Mouth, and says that after waiting for so long, his dream is finally coming true. Many have compared this to fanboying.
- Limited Wardrobe: A blue striped shirt and jeans. Remarkably similar to Steve's outfit.
- Remember the New Guy?: Despite not knowing how to play Blue's Clues until his debut episode, everyone at the house appears to already know him.
Blue's Clues House residents
- Color-Coded Characters: The residents of the Blue's Clues House make up the whole spectrum, with each character having a different main color. Pail: red, Sidetable: orange, Shovel: yellow, Steve: green, Blue: blue, Slippery: lavender, Mailbox: purple, Tickety: pink, Paprika: dark brown, Cinnamon: light brown, Mrs. Pepper: gray, Mr. Salt: white. When Joe debuted, he changed the colors of his shirts, breaking the spectrum rule a bit.
The title character, a blue spotted dog. She communicates with her owners by leaving trails of paw print clues.
- Afraid of Needles: She was a bit afraid to get her injection in one episode.
- Amazing Technicolor Wildlife: A blue dog.
- Cartoon Creature: Blue fur aside, she seems to be an ambiguous-looking breed of dog.
- Character Tics: Runs in place when happy sometimes.
- Color Character: Her name is Blue.
- Genki Girl: She seems quite vibrant and enthusiastic.
- Inexplicably Awesome: Able to jump "skidoo" into and out of pictures and leave blue paw prints on everything with no explanation as to how.
- Intelligible Unintelligible: She cannot speak, but her friends understand her pretty well.
- Nearly Normal Animal: It's unknown where she fits on the Sliding Scale of Anthropomorphism. She can understand English, use the human toilet, eat human food, brush her teeth, and go to school, but she walks on all fours and can't talk.
- Sick Episode: In the book "Blue's Sniffly Day", she catches a cold.
- Suddenly Speaking: Gains the ability to talk verbally in Blue's Room. Some of the later book releases also depict her as talking freely to the other characters in normal English.
- Animate Inanimate Object: Is a talking mailbox.
- Birthday Episode: "Mailbox's Birthday," the third episode of the entire series, is about Mailbox turning 10 years old.
- Catchphrase: "Here's ya letter!", "You got an e-mail!" and "You're welcome!", both said while exaggerating his Brooklyn accent.
- Cheery Pink: He's bright purple with a pink flag, and he's very cheerful.
- A Dog Named "Dog": A mailbox named "Mailbox".
- Image Song:
- There's a little chant that repeats the word "mail time" to indicate his arrival.
- Then Steve sings "We just got a letter", while Josh sings "We just got an e-mail" afterwards.
- Inexplicably Awesome: His extendo arm allows him to zoom anywhere in a split second, even when it makes no sense and shouldn't be able to stretch nearly that much.
The keeper of the Handy Dandy Notebooks. The hosts visit Sidetable before each game of Blue's Clues. She is shy and soft-spoken and has a hidden talent for singing. In the original series, she was also the keeper of Steve's telephone.
- Animate Inanimate Object: She's a talking side table.
- The Blank: When she's not talking, she switches to an "inanimate form" with no face. She is the only one of the main characters who does this, despite how most of them are also talking objects like her.
- Extreme Doormat: She always wants to be a part of the action, but she's a complete pushover. In the movie, she really wants to be Blue's partner in the show, but she's too afraid to say anything and accepts the menial job of ticket-collector.
- In-Series Nickname: Steve and Joe usually just call her "Sidetable."
- Mister Strangenoun: The name is three words.
- Satellite Character: For most of the first season, she only interacted with Steve. She eventually gained a more fleshed-out personality and relationships with the rest of the cast.
- Shrinking Violet: Best shown in Blue's Big Musical Movie, where she wants to sing, but is too nervous to ask.
A family of spice shakers. Mr. Salt and Mrs. Pepper are the parent figures of the house, who are always prepared to help Blue with some advice or a snack. They have four kids: Paprika, Cinnamon, and two baby twins named Sage and Ginger.
In "Blue's Big Holiday," it is shown that Mr. Salt and Mrs. Pepper are also the owners of the house. The flashbacks reveal that they raised Steve and Joe themselves.
- 100% Adoration Rating: Paprika, Cinnamon, Sage, and Ginger. Both of them are just as adorable.
- Age Lift: Both Paprika and Cinnamon are significantly older in the reboot series, Blue's Clues & You!. Paprika is now a teenager, while Cinnamon is a young boy whose cap now resembles a baseball hat.
- Animate Inanimate Object: A family of spice shakers.
- Anthropomorphic Food: Well, food shakers.
- Baby Talk: Paprika does that when she was a baby. She started to speak in complete sentences as a toddler.
- Cheerful Child: Paprika. She was often one as an baby, moreso as a toddler.
- Crossdressing Voices: In the original show, Cinnamon was voiced by Nick Balaban's daughter, Annalivia Balaban.
- The Diaper Change: Cinnamon has his diaper changed and it was a plot point in "The Baby's Here".
- Edible Theme Naming: With Mr. Salt and Mrs. Pepper, their last names are to do with food, with the kids it's their first names.
- Last-Minute Baby Naming: Paprika named Cinnamon on the first day of his life, after deciding that "he looks like a Cinnamon".
- Nice Hat: In the reboot, Cinnamon's shaker cap resembles a backwards ball cap to reflect he's gotten older.
- Plot-Relevant Age-Up: Cinnamon is now a small child in the reboot, with his shaker cap sporting a backwards flap to reflect the age.
- Supreme Chef: Mr. Salt is a good cook.
Two sandbox toys who live in the backyard. They accompany the hosts whenever a game of Blue's Clues takes place outside. They are interested in all kinds of plants and wildlife, and they want to be veterinarians when they're older. They are a brother (Shovel) and sister (Pail).
- Animate Inanimate Object: Two talking sand toys.
- A Dog Named "Dog": A shovel named "Shovel" and a pail named "Pail".
- Dub Name Change: In the UK adaptation, their names are changed to Spade and Bucket, since those terms are far more common in British English.
- Friend to All Living Things: They love all of the animals they find outside, and they want to be veterinarians when they're older.
- Friend to Bugs: They're good friends with Snail.
- Outdoorsy Gal: Pail.
- Palette Swap: Shovel is yellow with a red mouth, while Pail is red with a yellow mouth.
- Speaks Fluent Animal: Shovel and Pail are occasionally shown talking to (and understanding) non-anthropomorphic animals, such as a friendly gopher who shows up in early episodes.
The alarm clock who wakes the residents of the Blue's Clues House each morning. She is very number-oriented, likes to keep schedules, and often helps the host out with basic math. She lives on Blue's nightstand.
- Alliterative Name: Tickety Tock.
- Animate Inanimate Object: A sentient clock.
- Cue O'Clock: She has the ability to display a symbol related to whatever's happening in the episode in the 12 position.
- Good with Numbers: Tickety has a knack for math.
- In-Series Nickname: Sometimes gets called just "Tickety".
- Meaningful Name: Was named that because clocks go "tick-tock".
- Odd Friendship: With Slippery.
Tickety's best friend, a bar of soap who lives in the bathroom sink. He is very clumsy and tends to slide around wherever he goes. He dreams of becoming the captain of a boat when he grows up.
- Alliterative Name: Slippery Soap.
- Catchphrase: "Whoaaaa!"
- I Meant to Do That: Often says something like this after messing up.
- The Klutz: He is extremely clumsy and can't get around without slipping and sliding. He usually takes his clumsiness in stride, with the exception of Blue's Big Musical Movie, in which his slipping almost ruins the show and makes him want to give up. Slippery's friends use a song, "Don't Give Up," to help him feel better and go on with the show.
- Meaningful Name: Is a bar of soap and he often slips on himself.
- Mister Strangenoun: His name is an adjective and a noun.
- Odd Friendship: With Tickety.
Another dog, who lives nearby.
A dog who goes to Blue's school.
Another classmate of Blue's.
A classmate of Blue's.
A cat who lives nearby and likes to do magic tricks.
- Color Character: Light periwinkle.
- Girlish Pigtails: Hers are moon-shaped.