A cap badge, also known as head badge or hat badge, is a badge worn on uniform headgear and distinguishes the wearer's nationality and/or organisation. The wearing of cap badges is a convention commonly found among military and police forces, as well as uniformed civilian groups such as the Boy Scouts, civil defence organisations, ambulance services (e.g. the St. John Ambulance Brigade), customs services, fire services etc.
Cap badges are a modern form of heraldry and their design generally incorporates highly symbolic devices. Some badges that contain images of lions or other cats are sometimes informally referred to as cat badges.