- Voiced by Bob West originally. Now voiced by Dean WendtPerformed by David Joyner, then Carey Stinson
A purple Tyrannosaurus rex who comes to life through the imaginations of young children. Starting out as a plush toy, when the kids imagine, Barney arrives and helps the children learn various lessons on life.
- Carnivore Confusion: Although he's a T. rex, Barney is mostly vegetarian.
- Cuddle Bug: He loves hugs, making him fit this trope to a tee.
- Friend to All Children
- Magical Guardian
- Mr. Exposition
- Really 700 Years Old: Barney is over two hundred million years old. Justified in that he's a T. rex, but it's still a wonder that he can still be light on his feet.
- Say My Name and The Glomp: He gets this almost every day.
- Simpleton Voice: In early seasons. Subverted in that Barney's a pretty smart dinosaur, in context.
- Sleep-Mode Size: Barney has this in the form of a plush toy.
- Supernatural Is Purple
- Trademark Favorite Food: Peanut butter and jelly sandwiches, especially with a glass of milk.
- Tyrannosaurus rex
- Voiced by Julie JohnsonPerformed by Jenny Dempsey (1992), Jeff Ayers (1993-2008), and Lauren Mayeux (2009-present)
A three year old green triceratops, who is BJ's younger sister and one of Barney's best friends.
- Annoying Younger Sibling
- Baby Talk: Most notably in her early appearances, but still pops up from time to time.Baby Bop: [singing Home on the Range] Where the deer and the cantaloupe play...
- Large Ham: When she's not shy...
- Palette Swap: Of Barney himself.
- Start My Own: How she responded to learning that she was too young for the elementary school.
- Voiced by Patty WirtzPerformed by Jenny Dempsey (1993), Jeff Brooks (1994-2000), Kyle Nelson (2002-2009), Jared Harris (2010)
BJ is a seven year old yellow protoceratops who is Baby Bop's older brother.
- Annoying Older Sibling
- Big Eater: He's had more than one stomach ache. At the sight of the table spread in Sing and Dance with Barney, he loses control.
- Captain Superhero: Captain Pickles, a nod to his favorite snack.
- Nice Hat: In one episode, he loses it.
- Tuckerization: Named for Sheryl Leach's father.
- Youthful Freckles: They're purple.
- Voiced by Michaela DietzPerformed by Adam Brown (2006-2007) and Jerad Harris (2008 to present)
A six year old orange hadrosaur that is BJ and Baby Bop's cousin. He loves music and inventing new things.
- Bungling Inventor: A number of Riff's inventions go wrong. One episode had him invent a robot he dubbed "Litterbot," who was meant to clean the park. Eventually, it makes a bigger mess and Hilarity Ensues.
- Meaningful Name: Riff: (noun) "A repeated instrumental melody line in a song."
- Saying Sound Effects Out Loud
- Verbal Tickety Tick
- Embarrassing First Name: Averted. Mr. Boyd's first name is Grady, as revealed by his niece Colleen. This surprises the other kids, but it doesn't embarass him at all.Colleen: Oh, Uncle Grady...Rest of the kids: Grady!?Mario: I thought your first name was "Mister."
- Jack-of-All-Trades: While Mr. Boyd's main professions were being a janitor and a park keeper, he has also been a beach store owner and a bee keeper, as well as a talented musician. In The Best of Barney, he returns to visit Barney and co, now a photographer.