Osteomas are slow-growing, benign bony tumors. Most are asymptomatic. Paranasal sinus osteoma in the pediatric population is rare; hence, there are few reports of symptomatic osteomas. The authors report the case of a giant ethmoid sinus osteoma in an 11-year-old girl who presented with diplopia and proptosis. Total excision and reconstruction of the medial orbital wall were performed via a coronal approach. The postoperative period was uneventful, the child's vision improved, and a good cosmetic result was obtained.