If you have just welcomed a French Bulldog puppy into your family, you might be carefully examining every little detail of your new best friend. Occasionally, new owners notice that their puppy’s lower jaw protrudes slightly beyond the upper jaw and worry that this might be a defect.
Rest assured, a slight underbite is not a flaw—it is a required characteristic of the breed!
Here is everything you need to know about the French Bulldog jaw structure and what is considered normal according to official standards.
1. The AKC Breed Standard: The “Undershot” Jaw
French Bulldogs are a brachycephalic (flat-faced) breed. To achieve their signature pushed-in face and square head, their jaw structure must be specifically aligned.
According to the official American Kennel Club (AKC) breed standard, a correct French Bulldog jaw must be:
“Broad, deep, square, undershot, and turned up.”
“Undershot” is the technical term for an underbite. This means that the lower jaw naturally extends slightly past the upper teeth. If a Frenchie had a “level bite” (where the top and bottom teeth meet perfectly flush) or an “overshot bite” (where the top jaw is longer), it would actually be considered a structural fault!
2. The 1-Millimeter Rule & Puppy Growth
If you notice that your puppy’s lower jaw sticks out by a millimeter or so, congratulations—your puppy is developing beautifully!
A slight protrusion is exactly what breeders and show judges look for. It is also important to remember that puppies are constantly growing. Their skulls, upper jaws, and lower jaws can grow at slightly different rates during their first year. A mild underbite in puppyhood shows that their classic Frenchie face is forming correctly.
3. When Does an Underbite Become a Fault?
While an underbite is required, there is a limit to how extreme it should be. The golden rule for a healthy and structurally sound French Bulldog bite is simple:
- The acceptable limit: When the dog’s mouth is completely closed, the lips should cover the teeth perfectly.
- The fault: The underbite is only considered too extreme if the teeth or the tongue are visible while the mouth is naturally closed, or if the jaw is noticeably twisted to one side (known as a “wry mouth”).
4. Form Follows Function
This specific jaw structure isn’t just for looks; it is a historical hallmark of bulldog breeds. While your puppy will be using their mouth mainly for giving kisses and chewing on toys, their jaw is structurally designed to be wide and strong.
The Bottom Line: If your vet or a friend points out that your Frenchie has a slight underbite, you can proudly tell them that your dog simply has the perfect, classic French Bulldog conformation!