The anatomic abnormalities found in dogs with brachycephalic obstructive airway syndrome lead to changes in airway resistance and turbulent airflow. Altered airway resistance leads to secondary airway changes. All these changes cause airway noises, which may be present at rest or elicited during exercise. Exercise tolerance tests, careful respiratory auscultation, and identification of increased effort respiratory can help to grade brachycephalic dogs into different categories based on disease severity. Other categorization systems and multiple surgical procedures aim to stratify and alter the anatomic abnormalities leading to clinical impairment. Multiple anatomic sites should be addressed based on the anatomic abnormalities.