Why Some Dogs Slip Straight Out of a Perfectly Sized Harness

A correctly sized small dog harness can still fail if it sits in the wrong place on your dog's body, which is why so many owners find their dog backing straight out of one despite following the size chart. The issue is rarely the size number itself, it is where the chest strap actually sits relative to your dog's shape.


Small breeds vary enormously in how their chest narrows from the widest point down to the waist. A Chihuahua or Pug has a fairly compact, even shape, so a standard harness sits securely without much risk of sliding. A Whippet or Italian Greyhound has a much deeper chest and a narrow waist behind it, meaning a chest strap that sits even slightly too far forward has room to slide right off, especially if the dog pulls backward when startled.

According to VCA Animal Hospitals, a well fitted body harness puts minimal pressure on delicate neck tissue and is a genuinely better option than a collar for dogs prone to neck or airway sensitivity, which describes most small breeds to some degree. But well fitted is doing a lot of work in that sentence. The chest strap needs to sit close behind the front legs rather than anywhere near the throat, and the girth strap needs to be snug enough that two fingers fit underneath but no looser than that.

A step in or Y shape design tends to hold better on narrower framed small dogs than a design that goes over the head, since there is less loose fabric near the neck for a dog to twist and slip through. Multiple adjustment points matter more here than they do on a larger, more evenly shaped dog, since a harness that only adjusts in one place cannot account for the difference between a Chihuahua's chest and a Whippet's.

If your dog has ever backed out of a harness, the size was probably not the actual problem. Explore Happup's range of dog harnesses, collars and leashes to find a design built for a smaller, more particular frame.