Curious George is a production of Universal 1440 Entertainment (Universal Studios Family Productions before 2013), Imagine Entertainment, and WGBH Boston, and animated by Toon City. Each episode has two short cartoons per half-hour episode and a live-action segment after each story.
The series illustrates and explains various concepts in math and science and each live-action segment shows schoolchildren engaging in experiments that teach the math or science concept featured in the previous cartoon.
- The City: George and the Man with the Yellow Hat live in an apartment in "The City". The Doorman keeps a pigeon coop on the roof and is the guardian of Hundley, his dachshund dog. The apartment is near Endless Park, the museum where Professor Wiseman works, and a zoo. Chef Pisghetti's restaurant is nearby, as are a donut shop, Dulson's Toy Store, Mabel's Department Store, a supermarket and a pet shop. These are recurring locations.
- The Country: George and the Man with the Yellow Hat vacation in a small house in the country. The house is near Lake Wanasink Lake, a stream, and a river that eventually flows past the city and to the ocean.
- Curious George: George, a tailless monkey, is the show's title character. As his name implies, he's very curious, a trait which helps him to learn, but which also often gets him into trouble. He's used as the "teachable" character in the show, & he's the one to whom new concepts are explained in detail by the other characters; the viewers learn the new concept along with George. He's voiced by Frank Welker.
- Hundley: The Doorman's dachshund. He's a very neat dog who wants his lobby clean, tidy, & dignified. He doesn't care for George, as the lobby frequently becomes messy as a result of George's activities. Hundley's allergic to some cats, including Professor Wiseman's kitten Lucky, but not to Chef Pisghetti's cat Gnocchi. He's voiced by Jim Cummings.
- Compass: The Doorman's homing pigeon, who has a terrible sense of direction. Because of this, he's referred to as an "Almost-Homing Pigeon". Rob Paulsen provides Compass' cooing.
- Jumpy Squirrel: George's squirrel friend who likes to stay in trees, but often gets caught up in George's adventures in the country. He doesn't like surprises. A recurring joke in the serie's when Jumpy gets caught in a situation with George & the narrator says "At that moment Jumpy remembered why he always stayed in trees." He's voiced by Jim Cummings.
- Gnocchi: Chef Pisghetti's pet cat, who's often caught up in George's adventures. She frequently removes or loses her blue bow, which Chef Pisghetti replaces. She's voiced by Frank Welker.
- Charkie: A black cocker spaniel. She's very bouncy & playful & she often escapes from home. She's voiced by Rob Paulsen.
- Bill's Bunnies: There are 7 baby bunnies that belong to Bill. Their names are Fuzzy, Whitey, Brownie, Spotty, Black Ears, Cotton Tail, & Herbert Nenninger. He also owns their mother (Ma Rabbit), whose burrowing abilities are important in several episodes. They're all voiced by Frank Welker. (In Curious George's Bunny Hunt, Herbert Nenninger's a brownish-tannish color. In Bee is for Bear, he's white. However in Curious George's Bunny Hunt, the only white bunny's Whitey.)
- The Man with the Yellow Hat: The man who first befriended George & also acts as his primary teacher. He doesn't wear his hat while at home but always puts it on while going out. It's unclear what he does for a living, but in Curious George and the Invisible Sound he has been asked to survey animals around the country house, & in The Fully Automatic Monkey Fun Hat Dr. Wiseman has asked him to give a speech about the scientific method. He owns a country house that has been in his family since his childhood. He also paints in the style of the H.A. Rey drawings. He won an award for being the 1st to climb & map what became known as Yellow Hat Mountain & placed 17th in a marathon. He's voiced by Jeff Bennett.
- The Doorman: The doorman for the apartment building that George & the Man with the Yellow Hat live in. When on duty, he wears red clothes like a British Sentry Guard but with a red cap. When he went camping with George & Hundley, he wore an outfit somewhat similar to that of a Canadian Mountie. He's very friendly & always loves to see George. He keeps a coop of homing pigeons on the roof of the building. Like the Man with the Yellow Hat, the Doorman's name's never mentioned. He's voiced by Rob Paulsen in the 1st season & Carlos Alazraqui in the 2nd & current season.
- Professor Wiseman: A scientist friend of George & the Man. In different episodes she's seen to be a rocket scientist and to work at a local museum. She's voiced by Rolonda Watts.
- Chef Pisghetti & Netti: An Italian chef & his wife who own a restaurant in the city. The Chef has always wanted to cook & is always trying strange new recipes. His name's a reference to the way some toddlers pronounce the word "spaghetti." The chef's voice's provided by Jim Cummings & Netti's is by Susan Silo.
- The Renkins: A couple who own a farm near the country house. They have horses, cows, pigs, chickens, & bees, all of which provide sources for adventures. George also sometimes borrows materials from them, including a water pump & scrap lumber. Mr. Renkins is voiced by Jeff Bennett. Mrs. Renkins is voiced by Elizabeth Daily.
- Bill: George's neighbor from across the street in the country. He owns a hutch of bunnies & has a paper route. He also likes to fly kites, but seems to be an acrophobic. His catchphrase is, "There's a proper way to ...." Bill apparently doesn't realize that George's a monkey & often refers to him as a "city kid." Bill's voiced by Annie Mumolo.
- Steve and Betsy: 2 Children from George's neighborhood in the city who are brother & sister. They live with their Aunt Margaret & their dog, Charkie. Steve likes video games & is always "going for a record" of some kind. He's the older child of the pair, & is always getting ideas about how to solve a problem. He often tells George, "I'm in 5th grade. This has to work." In the episode Piñata Vision, their Aunt called him by his full name, Steven. Betsy's often pulling a red wagon. Steve's voiced by Elizabeth Daily & Betsy's voiced by Grey DeLisle.
- Mr. Glass: Owns a building known as "The Glass Palace" & hires window washers in the City. George uncovers a catastrophic flaw in a building which Mr. Glass was constructing. He likes things to be unique ever since George painted a jungle-themed room in The Glass Palace. Voiced by Rob Paulsen.
- Mr. Zoobel: George's upstairs neighbor in the City. Mr. Zoobel's a painter in a modern (non-representational) style who sometimes uses stamps shaped like animal feet. He has a de-scented pet skunk named Geoffrey, a gopher snake named Bruno, & 2 mice named Benjy & Willy. He sometimes gets carried away making his art. When he 1st moved in, he used the stamps so much it made a loud stomping noise in George's apartment downstairs making George think he lived with an elephant. He's voiced by Jim Cummings.
- Benji & Willie: Mr. Zoobel's pet mice who are respectively black & white. They feel cooped up in their small terrarium and long for freedom. They are afraid of Zoobel's gopher snake Bruno because of the fact that snakes eat mice. Their squeaks are by Frank Welker.
- Bruno: Mr. Zoobel's pet gopher snake who only eats once a day. He sheds his skin 3 times a year. Like many snakes, he likes sunshine. He has no voice.
- Doxie: Doxie is another dachshund who was introduced in Season 2. She is almost identical to Hundley in appearance, except that she wears a red collar; however, unlike Hundley, Doxie is bouncy and playful and is voiced by Frank Welker, not Jim Cummings.
- Fluffy: In the episode Monkey Fever, Fluffy was a cat who belonged to Betsy's friend and had six kittens. Betsy brought one of the kittens over to George's apartment to show him. Voiced by Frank Welker.
- Geoffrey:Mr. Zoobel's pet skunk. He is de-scented and domesticated.
- Leslie: Leslie is a cow, owned by the Renkins. She's a great friend of George. Voiced by Rob Paulsen.
- Little Mike: Mike is a pig owned by the Renkins. He first appears in Ski Monkey, when he is stranded in the snow. He also appears in Old McGeorgie had a Farm.
- Lucky: Lucky is Professor Wiseman's kitten, introduced in season 2. She likes Hundley, although Hundley is allergic to her. Lucky is voiced by Debi Derryberry. Voiced by Frank Welker.
- Oscar: A white pig owned by the Renkins who won the "prettiest pig" contest in (Old McGeorgie had a Farm).
- Soo Berm: An elephant who works at the zoo as a painter. Every one of her paintings is unique. She signs a painting by marking it with her trunk with green paint when she is done.
- Tracy: Tracy is a hen, owned by the Renkins. She has five (Up the River) or six (Old McGeorgie had a Farm and A Bridge to Farm) chicks who follow her around everywhere. The chicks also like George and often follow him around too. The chicks are curious just like George and are often wandering away from Tracy. The youngest of her chicks is named Al. Voiced by Rob Paulsen in the first season and Frank Welker in the second.
- Ada & Luke: A couple who own a general store in the country. The store gives a free pickle to anyone who comes and visits. Eva is voiced by Kath Soucie and Luke by Rob Paulsen.
- Andie, Stig, & Stew: Firefighter members of Rescue Squad 86 who play in a band with the Man with the Yellow Hat. They are confused as to why they never get "normal" calls. Andie is voiced by Elizabeth Daily, Stig by Rob Paulsen in season 1 and Jim Cummings in season 2 and Stew is voiced by Kevin Michael Richardson.
- Calhoun The Gopher Getter: A gopher exterminator in the country who is nerdy and has buck teeth. He was hired by Mr. Renkins to eliminate a gopher family that was taking his grapes. After Calhoun resorted to bulldoze the Renkins' garden at a last attempt to catch the gophers, he was fired by Mr. Renkin. Oddly enough he looks similar to a gopher himself. He is voiced by Rob Paulsen.
- Cayley: Cayley owns a candy counter in Mabel's department store (a parody of Macy's, and likely a portmanteau name referencing both Macy's and its erstwhile competitor Gimbel's) in New York City. She is voiced by Kari Wahlgren.
- Dorothy: Dorothy is the Doorman's sister. Voiced by Grey DeLisle.
- Dr. Alvin Einstein: A rocket scientist who works with Dr. Wiseman and Dr. Pizza. He is not related to the famous scientist Albert Einstein. He often argues, fights and bickers with Professor Anthony Pizza over less-than-functional elements of a spaceship's design. He is voiced by Jim Cummings.
- Dr. Baker: Dr. Baker is The Man with the Yellow Hat's doctor. He is voiced by Kevin Michael Richardson.
- Dr. Ghesund: Another doctor who works in the same office as Dr. Baker. His name is similar to the German word for "bless you", "Gesundheit." Voiced by Dee Bradley Baker.
- Dr. Raj Desai: A scientist that dug up all of the city Museum's dinosaur skeletons. He is very caring of his discoveries and only lets other scientists handle them. He is very forgetful though and his wife often tells him he'd forget his head if it weren't attached. His newest donated project to the museum had the incorrect skull; the skull to the older skeleton next to it.
- Grocer: He owns the grocery store near George's apartment building in the city, and has an adult son who helps him run the store. Voiced by Jim Cummings.
- Gwen & Sisly: The respectively White & Black women who work at the city dog pound.
- Mr. (Ken) Auger: A plumber always hired by The Man In The Yellow Hat to fix household plumbing problems. He always lets George watch him do his job. He is distressed at the fact that people never just call him over for a friendly visit.
- Mrs. Dulson: The eccentric owner of Dulson's Toy Store in the city. Her husband appears in Roller Monkey.
- Mr. and Mrs. Quint: Mr. Quint is one of George's country friends, Clint Quint is an avid fisherman and one of a set of quintuplets. His siblings are a sister who is a track runner (Sprint), a brother who is a train-station master (Flint), a brother who is a police officer (Wint), and a sister who prints money (Mint). All male Quints are voiced by Jim Cummings. All female Quints are voiced by Candi Milo.
- Mr. Reloj: Mr. Reloj owns a clock store and knows everything all about them. He walks very fast, but is forever late. His name is the Spanish word for clock. He is voiced by Dee Bradley Baker.
- Mrs. D.: Mrs. D. is an owner of a donut store in the city. Voiced by Kath Soucie.
- Mr. Ruffweek: A blimp pilot who flies the Ruffweek Blimp. The blimp flies over 7 N. Avenue once in the morning, and again at sunset. His name is a play on the words "Rough Week", perhaps referring to his tight schedule or a play on the "Good Year" Blimp. Voiced by Rob Paulsen.
- Professor Anthony Pizza: Another scientist who sent George on a mission. He is often arguing, fighting and bickering with Dr. Alvin Einstein over who came up with the idea for a non-functioning element of the spaceship's design. Voiced by Dee Bradley Baker.
- Rodney: An employee of a market in the city. (This market is not the grocery store which George normally visits; it is nearby street, and serves as that store's main competitor.) Rodney lost the annual Bag-A-Lympics competition due to his overconfidence. Voiced by Jim Cummings.
- Uncle Tam: The Man With The Yellow Hat's cousin, who dresses in green clothes with a white shirt and lives in a castle in Scotland with a golf course. In the episode Castle Keep, he was going to be evicted from his castle because he could no longer find the castle's deed, which meant he would have to pay 400 years of back taxes. Voiced by Dee Bradley Baker.
- Zucchinis: A family of three acrobats renowned for their balance. They are friends of Chef Pisghetti. Voiced by Dee Bradley Baker, Candi Milo, Kath Soucie and Jim Cummings.
- Allie Renkins: The 5-yr old granddaughter of Mrs. Renkins. Voiced by Lara Jill Miller.
- Dog Trainer Man A man that is involved with dog shows and competitions. Mainly seen in Curious George dog Counter and Charkie Goes To School.Curious George (TV series)
The setting for most episodes is either the city, where George lives in an apartment building with The Man in the Yellow Hat or the country, where they share a small house near a lake called Lake Wanasinklake. This allows George to mirror the experiences of kids who live in an urban environment and those who live on farms and in suburbs. A few episodes take place in alternate but familiar settings, like an airport or a train station.
A total of 9 seasons (108 episodes) have been aired. For a list of episodes, see 
- 2008 - Outstanding Children's Animated Program
- 2010 - Outstanding Children's Animated Program