The skull is flat and moderately narrow, tapering slightly toward the muzzle. Cheeks are flat and clean. The muzzle is strong and tapers slightly from stop to nose. Jaws are strong and muscular. There is a minimum of falling away under the eye, giving a moderately chiselled look.
Lips are tight and darkly pigmented.
The Smooth Fox Terrier has a complete set of comparatively large, evenly spaced, white teeth with a scissors bite. The nose is black and fully pigmented. Eyes are deep set, moderately small, nearly round, dark in color, with a lively, intelligent, sometimes fiery expression. Eyerims are darkly pigmented. The Smooth Fox Terrier has small, V-shaped, button ears of moderate thickness.