Granulomatosis with polyangiitis (GPA) is a rare, small-vessel vasculitis that often presents with upper and lower respiratory tract symptoms along with nonspecific symptoms, including fever and weight loss. Although it is more likely to present in adulthood, GPA can present at all ages and affect multiple organ systems, making its recognition exceedingly difficult and leading to delayed diagnosis. This is particularly deleterious in the pediatric population in which delayed diagnosis and treatment are associated with a significantly worse prognosis, significant hematologic complications, and irreversible organ damage. We discuss a 14-year-old boy with GPA who presented with noncardiac chest pain and polyarthralgias in whom a detailed review of systems later revealed a 2-year history of fevers, malaise, and failure to thrive. Our report reveals the importance of early recognition and treatment of GPA during childhood. [ABSTRACT FROM AUTHOR]