Secret Squirrel is a cartoon character created by Hanna-Barbera and also the name of his segment in The Atom Ant/Secret Squirrel Show, which debuted in 1965. He was given his own show in 1966, titled The Secret Squirrel Show, but was reunited with Atom Ant for one more season in 1967. The half-hour The Secret Squirrel Show included three individual cartoon segments: Secret Squirrel, Squiddly Diddly and Winsome Witch. Secret Squirrel first appeared in a prime-time animated special called The World of Secret Squirrel and Atom Ant, which aired on NBC on September 12, 1965.

Secret Squirrel was a parody of the spy genre, and most of the shorts parodied elements of the James Bond films. Secret Squirrel was also known as Agent 000. In 1993, 13 new Secret Squirrel cartoons appeared in-between the 2 Stupid Dogs first-season episodes, with the updated title Super Secret Secret Squirrel and a new cast.