There is a minimum of falling away under the eye, giving a moderately chiseled look. Lips are tight and darkly pigmented. The Jack Russell Terrier has a complete set of comparatively large, evenly spaced, white teeth. A scissors bite is preferred, but a level bite is acceptable. The nose is black and fully pigmented.
Eyes are deep set, almond-shaped, dark in color, with a mischievous, intelligent expression.
The Jack Russell Terrier has small, V-shaped, button ears of moderate thickness. The ears are set at the outside edge of the skull and the tips are carried close to the head. Any ear carriage other than button. The neck is clean, muscular, and of sufficient length to enable the dog's mouth to extend beyond its forepaws when working underground. The neck gradually widens from the nape and blends smoothly into the shoulders.