The epiglottis is a flexible flap of cartilage covered with mucous membrane in mammals that is attached to the wall of the pharynx near the base of the tongue. During swallowing it covers the glottis (the opening to the respiratory tract) and helps to prevent food from entering the trachea (windpipe), although it is not essential for this purpose.

The epiglottis becomes swollen and inflamed in the childhood condition of acute epiglottitis and may cause respiratory obstruction.