Gun dogs or bird dogs are types of hunting dogs developed to assist hunters in finding and retrieving game, typically various fowls that are shot down on the flight. The term hunting dog is broad and includes all breeds and skills of hunting canines, but "gun dogs" refers to canines that are trained to work alongside a loud firearm while hunting or retrieving game. Gun dogs are divided into three main categories: pointers and retrievers, setters and spaniels, and water dogs.

Dog types are broad categories of domestic dogs based on form, function, or style of work, lineage, or appearance. Some may be locally adapted dog types that may have the visual characteristics of a modern purebred dog. In contrast, modern dog breeds strictly adhere to long-established breed standards,[note 1] that began with documented foundation breeding stock sharing a common set of inheritable characteristics, developed by long-established, reputable kennel clubs that recognize the dog as a purebred.