In this article, we report a rarely localized sacral aneurysmal bone cyst (ABC) successfully treated by curettage and bone grafting with fresh frozen fibular allograft (FFA) in a 14-year-old girl patient. The cyst was at S1-2 level and treated with aggressive curettage and bone grafting with two FFAs. All complaints of the patient resolved at the 24th month of treatment and bony union of the cystic cavity was observed radiologically. Curettage and FFA may be safely used for filling the cavity in the treatment of sacral ABC in pediatric age to provide a structural and biological reinforcement.