A glass run for use in a motor vehicle, which is capable of preventing seal lips from closely contacting inner surface of side walls thereof, and accordingly preventing the generation of noise therein. An opening-side groove is formed in an inner surface of an outside wall near an open end thereof to define a space between the inner surface of the outside wall and a base of the outside seal lip when an end of an outside seal lip contacts the inner surface of the outside wall. And a bottom-side groove is formed in the inner surface of the outside wall so as to receive the end of the outside seal lip which is pushed by the door glass. A protruding part having a rib is further formed in the inner surface of the outside wall so as to contact the widthwise middle of the outside seal lip which is pushed by the door glass.