It is square when viewed from above and the circumference of the muzzle is equal to two-thirds the circumference of the skull. The top line of the muzzle rises slightly from the stop to the nose, forming a very obtuse angle with the line of the forehead. The ideal is between these two extremes. When the head is held horizontally, the end of the muzzle extends beyond a vertical line drawn from the tip of the nose. The jaws are very broad and powerful.
Lips are thick and moderately pendulous.
When the mouth is closed, the upper lip hangs over side of the lower jaw. The chin is well defined and must neither overlap the upper lip nor be covered by it. The Dogue de Bordeaux has a complete set of large, evenly spaced, white teeth. The incisors are well-aligned, particularly the lower incisors which form an apparently straight line. An undershot bite is characteristic of the breed with the inside of the lower incisors extending in front of the upper incisors at least .2 inch and no more than three-quarters inch.