Vascularized free flaps have become the gold standard in reconstructing large segmental mandibular defects; however, even when bony union and soft-tissue coverage is achieved, insufficient bone stock and altered facial contour can create functional and cosmetic problems for the patient. There have been limited case reports on the use of secondary distraction osteogenesis to address these issues. The authors report a case of bilateral mandibular distraction of deep circumflex iliac artery free flaps, used for mandibular reconstruction after total mandibulectomy for treatment of osteosarcoma. Performed for reasons of retrognathia and facilitation of dental prosthetic rehabilitation, this is the first case of bilateral horizontal distraction osteogenesis of deep circumflex iliac artery free flaps reported in the literature.