Scrappy-Doo is the incorrigible and exuberant nephew of the cartoon dog Scooby-Doo in various incarnations of the Scooby-Doo cartoon series (Scooby and Scrappy-Doo (1979), The Scooby and Scrappy-Doo Puppy Hour (1982), The All-New Scooby and Scrappy-Doo Show (1983)). He has been voiced by both Don Messick and Lennie Weinrib.

A Great Dane pup who was born at St. Bernard's Hospital to Ruby-Doo, Scrappy idolizes his uncle Scooby and often assists his team in solving mysteries.

Fearless and energetic, Scrappy has often been vilified by some fans of the show. Opinion is divided but many fans blame Scrappy for an apparent downturn in the show's quality in the 1980s. Supporters argue that the downturn was due to poor quality writing and a breakaway from the show's traditional premise by including real ghosts, as well as a subsequent upturn for some of the later series.

It is notable that Scrappy-Doo was left out of the team for the 2002 Scooby Doo movies, as well as for the What's New Scooby-Doo series, primarily due to poor fan opinion of the character.

Thus, 'Scrappy Doo' is also a fan term for a character, usually overexuberant or cute in an irritating way, added to a series.