PURPOSE: To present a case of orbital myositis associated with herpes zoster ophthalmicus. DESIGN: Observational case report. METHODS: A 47-year-old woman with acute retrobulbar eye pain and diplopia preceding the vesicular rash of herpes zoster ophthalmicus was evaluated and treated. RESULTS: Magnetic resonance imaging showed enlargement and enhancement of extraocular muscles consistent with an inflammatory myopathy. Following acyclovir and prednisone treatment, all symptoms resolved, and neuralgia did not develop. CONCLUSIONS: Herpes zoster may cause symptoms and signs of orbital myositis before eruption of cutaneous skin lesions and thus should be considered in the differential diagnosis of an acute orbital myositis.