Giant cell tumour (GCT) or osteoclastoma is a very rare locally invasive bone tumour that occurs close to the joint. The ulnar metaphysis is an unusual site for an Osteoclastoma with occurrence rate of 0.45% to 3.2% as reported in literature [1]. Most of the patients seek traditional methods of treatment before orthopaedic consultation and present lately with extensive involvement of the tumour into soft tissues and articular surface, making the joint preservation difficult or impossible. For reconstruction, several options have been described, which include fibular autografts, allografts and cement augmentation. Inherent to all these procedures is the risk of delayed union of the graft and preserving functional mobility of the joint. We report a rare case of a proximal ulna GCT diagnosed in a 13-year-old girl. It was treated with intralesional curettage, and autologous maternal iliac crest bone grafting augmented with bone cement reconstruction.