We report the case of a 15-year old girl who presented with a non-tender right upper eyelid swelling. Magnetic resonance confirmed the presence of an enlargement of the orbicular muscle with moderate contrast enhancement. Biopsy revealed the presence of necrotizing granulomatous vasculitis. Further studies ruled out systemic involvement. Thus, she was diagnosed with isolated granulomatosis with polyangiitis (GPA). Treatment with steroids and methotrexate was started. Due to the persistence of the lesion, rituximab (RTX) was added with excellent clinical and radiological response. This is, to the best of our knowledge, the first case of isolated orbital GPA treated with RTX in a pediatric patient.