Companion dog usually describes a dog that does not work, providing only companionship as a pet, rather than usefulness by doing specific tasks. Many of the toy dog breeds are used only for the pleasure of their company, not as workers. Any dog can be a companion dog, and many working types such as retrievers are enjoyed primarily for their friendly nature as a family pet, as are mixed breed dogs. The American Kennel Club also offers a Companion dog title for judged dog obedience competitions.

Some people^[who?] and breed groups argue that any dog of a working dog type is inherently a working dog, while others^[who?] say that only a dog being actively worked, either in a related field such as water trials for retrievers or herding trials for herding dogs, or in some other field that requires training and discipline, such as being assistance dogs or participating in dog agility, can be considered a working dog.

Dogs that have been chosen for traits that make a convenient pet are generally smaller breeds, and the tradition of keeping pretty dogs for no purpose other than to be court decorations stems back thousands of years to Chinese nobility. The Pekingese and the Pug are both examples of canines chosen for their ability to be pets. In the case of the Pekingese, it was for their lion-like demeanor; for the Pugs, it was for their "lucky" wrinkles and their monkey-like face.