A 60-year-old woman presented with diplopia and left periorbital edema and pressure, which developed during an anxiety attack the previous day. Examination revealed left inferotemporal globe dystopia, periorbital edema, ecchymosis, and limitation in supraduction. Orbital MRI confirmed the diagnosis of a superior subperiosteal orbital hematoma. The patient's signs and symptoms rapidly resolved with administration of oral corticosteroids. The patient remains asymptomatic with complete resolution of orbital signs at 3-month follow-up. Subperiosteal orbital hematoma (SOH) is a rare condition in which blood accumulates between the bony orbit and separated periosteum, and is often due to blunt head trauma. Non-traumatic SOH (NTSOH) is exceedingly rare and usually associated with known coagulopathies or tendency to bleed. However, few cases of spontaneous NTSOH have been reported without any such predisposition and are thought to be caused by sudden elevations in intrathoracic and intracranial venous pressure such as vomiting, coughing, SCUBA diving, weight lifting and labor. We herein describe the presentation, radiography and outcome of a unique case of spontaneous NTSOH following an anxiety attack.