I am sure it would. It is stretchy material and I managed to get it on a fat cat just to try to see if it would fit-don't worry it's been cleaned. It's Body Glove brand and the tag says xs. But a 4 lb Chihuahua is xxs...lol.
Another thing... I listed it as kitty stuff cause if the toys, but I inherited the collars, harness/leash and outfit, so it's probably more dog. I figure take it all and pass it on.