This document provides information on headgear, including its components, principles of use, types, and applications in orthodontic treatment. Headgear delivers extraoral force from a cranial support to intraoral appliances. It consists of a facebow, force element, and head cap. Forces from headgear can distalize teeth and maxilla through different anchorage points. Types include cervical, occipital, and high pull headgear. Headgear is useful for orthopedic effects, anchorage reinforcement, molar distalization, and space maintenance.