Hyperparathyroidism is nowadays diagnosed early and asymptomatically with the improvements in routine biochemical tests and radiological procedures. The late bony complications of the disease have therefore started to decline rapidly. Brown tumours are one of the bony complications of hyperparathyroidism. The mandible is the predominantly affected site in the maxillofacial area. Maxillary involvement is rare. Here, an extremely rare case of a 19-year-old male patient with brown tumours in his maxilla and mandible associated with tertiary hyperparathyroidism is presented. A thorough diagnostic work-up was carried out and treatment options for both hyperparathyroidism and brown tumours were discussed. The importance of different radiological evaluation methods and the consultation between the oral and maxillofacial surgeons, general practitioner dentists, endocrinologists and radiologists are emphasised.