OBJECTIVES To describe the clinical, laboratory, histopathological presentations and final diagnoses for children presenting to a tertiary paediatric rheumatology service with an inflammatory lesion of the orbit. METHODS This was a retrospective descriptive case series of children with an inflammatory lesion of the orbit presenting to a single paediatric rheumatology service between January 1999 and July 2010. RESULTS Ten patients, median age 11.5 (range 3.1-16.2) years at referral to the paediatric rheumatology department were identified; median duration of symptoms at referral was 9 (0.75-17) months. Imaging was performed in 9/10 cases: orbital MRI (n = 4), orbital CT scan (n = 1), both MRI and CT scan (n = 4). All 10 patients had an orbital biopsy; 2 patients had repeat biopsies. The final diagnoses were granulomatosis with polyangiitis (Wegener's) (n = 5; ANCA positive n = 4, ANCA negative n = 1), idiopathic orbital inflammation (n = 3), atypical mycobacterial infection (n = 1) and sarcoidosis (n = 1). CONCLUSION Inflammatory mass lesion of the orbit is an unusual presentation in children. The differential diagnosis is wide and may evolve over time. Orbital biopsy and screening for systemic features is essential before treatment with CSs or other immunosuppressants to exclude malignancy, infection, vascular lesions, autoimmune conditions or other causes of orbital inflammation that can be associated with serious systemic manifestations.