PURPOSE: To report a case of subperiosteal orbital and subgaleal hemorrhage with optic nerve compromise in a patient with a factor IX deficiency. DESIGN: Interventional case report. METHODS: A 5-year-old male presented 10 days after mild trauma with progressive left-sided scalp swelling, proptosis, and visual loss. RESULTS: The patient had marked proptosis of the left eye, 20/200 visual acuity, and an afferent pupillary defect. Magnetic resonance imaging demonstrated a large subgaleal and left subperiosteal orbital hematoma. Quantitative assays of coagulation proteins identified a factor IX deficiency (Christmas disease). CONCLUSION: Delayed-onset subgaleal and subperiosteal orbital hematoma can rarely be an initial manifestation of Christmas disease.