This report is of a patient with a rare extramedullary plasmacytoma of the orbit as the initial manifestation of systemic multiple myeloma. A 34-year-old otherwise healthy man presented with periorbital pain for 2 weeks with proptosis, diplopia, and limited ocular motility in the left eye. Magnetic resonance imaging showed an extraconal mass at the superotemporal region of the left orbit with bony erosion and an enhancing orbital lesion in the temporal quadrant of the right orbit. Histopathological examination of the orbital mass revealed a plasmacytoma with lambda light chain restriction. Systemic evaluation revealed an immunoglobulin G myeloma with multiple myeloma in the first lumbar vertebra, hypercalcaemia, and renal impairment. Chemotherapy was planned. Plasmacytoma of the orbit is rare and can present as the first manifestation of multiple myeloma. Ophthalmologists should be aware of such a presentation and must act promptly. This report reviews the presenting features.