Abstract: Air inlets are disposed in the anterior surface of a racing muzzle for a dog to receive and channel air directly into the open mouth of the dog while the dog is running and breathing only through its mouth; further inlets in proximity to the dog's nostrils accommodate airflow during quiescent periods when the dog is breathing through its nostrils. Aerodynamically located openings promote exhaust airflow from the sides of the dog's mouth and minimize the presence of stale air within the muzzle.