The skull is flat and of moderate width, tapering slightly toward the muzzle. Cheeks are flat and clean. The muzzle is sufficiently wide and deep to balance the skull. The underjaw is strong. There is a minimum of falling away under the eye, giving a moderately chiselled look.
Lips are tight and darkly pigmented.
The Kerry Blue Terrier has a complete set of good-sized, evenly spaced, white teeth. A scissors bite is preferred but a level bite is acceptable. Nose is black with large, wide nostrils. Eyes are small, round, dark in color, and set moderately wide apart. Expression is full of fire and intelligence.