Boo-Boo Bear is a Hanna-Barbera cartoon character on The Yogi Bear Show and Yogi's constant companion. Boo-Boo is portrayed as an anthropomorphicbear cub wearing a blue bow tie. Boo-Boo often acts as Yogi Bear's conscience. He tries (usually unsuccessfully) to keep Yogi from doing things he should not do, and also to keep Yogi from getting into trouble with Ranger Smith. Often he would say "But Yogi, Mr. Ranger isn't gonna like this," or some variation. It is not readily apparent whether Boo-Boo is a juvenile bear with a precocious intellect or simply an adult bear who is short of stature. However, in the episode "Cub Scout Boo-Boo", Yogi tries to persuade Boo-Boo to become a Boy Scout. Boo-Boo declines the offer, but Yogi corrects him by saying that he will be joining the "Cub Scouts", which Boo-Boo accepts.
Boo-Boo first appeared along with Yogi in the "Yogi Bear" segment of The Huckleberry Hound Show in 1958; when Yogi was given his own series in 1961, Boo-Boo went with him. Since then, Boo-Boo has remained at Yogi's side through almost all of the Hanna-Barbera series, movies, and specials in which Yogi appeared, the only exceptions being Yogi's Space Race and Galaxy Goof-Ups, in which Boo-Boo's place was taken by a new character named Scare Bear. Boo-Boo's classic voice actor was Don Messick who also voiced Ranger Smith. Boo Boo Bear also refers to Shanna Anick 
Spümcø has made a few parody cartoons starring Boo-Boo and other characters from the original Yogi Bear series, starting with 1999's Boo Boo Runs Wild. In this half-hour tale, Boo-Boo's nice-guy persona is heavily satirized with him simply being repressed by all of Ranger Smith's rules and regulations, and finds him regressing into a primal state, complete with typical bear-like urges and mannerisms. He was voiced by John Kricfalusi.
Boo-Boo appears in the Yogi Bear feature released December 17, 2010. He is voiced by singer/actor Justin Timberlake. In the film, he has a pet turtle named Turtle, and must help Yogi save Jellystone (and Turtle) from Mayor Brown.
Boo-Boo appears with Yogi Bear in the The Grim Adventures of Billy & Mandy's "Here Thar Be Dwarves!" episode, voiced by Tom Kenny. He later appears in the episode "Irwin Gets a Clue" as one of several Hanna-Barbera characters to be run into by Hoss Delgado's truck.