Giant cell tumor (GCT) of bone is a relatively common benign bone lesion and is usually located in long bones, but involvement of the olecranon is extremely rare. Here, we present a case of solitary GCT of bone in the olecranon that was confirmed by preoperative needle biopsy and postoperative histological examination. The treatment included intraregional curettage, allogeneic bone grafting, and plating. At 26 months follow-up, the patient had no local recurrence.