Size guide by breed (we reccomend going off the : XXS: Chihuahua, teacup breeds and small puppies XS: Pomeranian, Dashound, Toy Poodle S: Cavoodle, M: L: XL: Labrador, Golden Retriever, Husky, Boxer Note: If your fur-babe is attempting to compete for a new World Record in the Strongman Pulling Event, this harness may not be suitable for you.