Barney Rubble is the secondary main character and Fred's best friend and next door neighbor. His occupation is, for the most part of the series, unknown, though later series depict him working in the same quarry as Fred. He shares many of Fred's interests like bowling and golf, and is also a member of the "Loyal Order of Water Buffaloes". Though Fred and Barney frequently get into feuds with one another (usually due to Fred's short temper), their deep fraternal bond remains evident.
- Barney met Winnie the Pooh and friends in Pooh's Adventures of The Flintstones Movie.
- Barney reunited with Winnie the Pooh and friends in Pooh's Adventures of The Jetsons Meet the Flintstones and Pooh's Adventures of The Man Called Flintstone.
- Barney guest starred in Pooh and Ash's Adventures of Scooby-Doo and the Headless Horseman of Halloween.
- Barney will guest star in Pooh's Adventures of The War of the Worlds (2005)..
- Barney will Meet Sora and Pals in Sora Meets the Flintstones. (As He will be Reavled to Be Trish's Uncle)