Greyhounds are considered the fastest dogs in the world. With top speeds of 45 mph, they wouldn’t catch a cheetah in a sprint, but they’re darn fast! Other similarly athletic sighthounds like Sloughis, Afgans and Salukis fly by at 40 and 42 mph. A little more surprising, perhaps, is the Vizla at 40 mph and, believe it or not, the Dalmatian at 37 mph! Zoom!