World Myositis Day is observed worldwide every September 21 to promote awareness of myositis, a rare condition characterized by inflammation of the skeletal muscles. The day was first recognized as Myositis Awareness Day in Massachusetts in 2001, organized by Janice Goodell from The Myositis Association. In 2023, various international myositis groups established World Myositis Day to coincide with the existing National Myositis Awareness Day in the U.S. Myositis includes several subtypes, such as dermatomyositis, polymyositis, and inclusion body myositis, and can result from autoimmune reactions, infections, or medications. The condition often presents with symptoms like progressive muscle weakness and extreme fatigue, making diagnosis challenging. Raising awareness is crucial for ensuring individuals receive appropriate diagnosis and treatment.