BACKGROUND: Osteomas are rare benign and slow-growing osteogenic tumors mainly involving frontal and ethmoid sinuses. OBJECTIVES: The primary objective of our study is to present the management of cases of giant frontal sinus osteomas. Secondarily, we describe our modified unilateral osteoplastic flap approach without obliteration to remove these osteomas. METHODS: Retrospective chart review at a tertiary academic center ("Hôpital de l'Enfant-Jésus") from July 2006 to October 2016. Demographics characteristics, tumor characteristics, presenting symptoms, frontal sinus surgery technique (osteoplastic flap, endoscopic surgery, or a combination of both), and outcomes of giant frontal sinus osteomas (≥30 mm) were recorded. For laterally placed osteomas, tumors with posterior wall involvement, orbital roof involvement, or intracranial extension, the modified unilateral osteoplastic flap approach was used. A decision-making algorithm is proposed for the choice of surgical approach. RESULTS: Ten giant frontal osteomas were analyzed (7 men and 3 women). The mean age at diagnosis was 38 years old (range, 24-55 years; median, 39 years; standard deviation, 11 years). The most common presenting symptom was headache (43% of symptomatic patients). Five patients had complications preoperatively due to tumoral extension (sinusitis, cellulitis, mucocele, optic nerve compression, and convulsions). One patient was treated endoscopically, 3 patients had an open approach and 6 patients had a combined technique. One patient experienced a postoperative complication (local infection treated with oral antibiotics). Six patients had minimal residual tumor with one patient needing reoperation. CONCLUSION: Osteomas are rare paranasal sinus tumors. Due to the proximity to noble structures, a giant frontal osteoma should be managed surgically. The modified unilateral osteoplastic flap without obliteration offers good long-term surgical and aesthetic results. Osteomas are not known for malignant transformation and recurrences are rare; thus, subtotal resection is warranted and safe when a cleavage plan is not found.