The skull is long and, although slightly domed, appears nearly flat in profile. The width of the skull is approximately equal to the length of the skull from occiput to stop. The skull is smooth with no prominences or depressions and the cheeks are flat and clean. The length of the muzzle is approximately equal to the length of the skull with only a slight taper to the nose. The muzzle is well filled in under the eye, with no evidence of snipiness.
Lips are close-fitting with dark pigment.
The Scottish Terrier has a complete set of large, evenly spaced, white teeth. A scissors bite is preferred but a level bite is acceptable. The jaw is square, level and powerful. The nose is black, regardless of coat color, and of good size, projecting somewhat over the mouth and giving the impression that the upper jaw is longer than the lower. The eyes are set wide apart and well in under the brow.