Which dogs are the dumbest? Written by Russel in A Which dogs are the dumbest? The Afghan Hound is considered the dumbest dog. Other dogs in this category include the Beagle, Bulldog, Bloodhound, Mastiff, and Basset hound. What humans consider dumb is low-IQ in dogs. Russel A pet owner who loves to share useful facts and information about a variety of animals.