Progressive sclerosing orbital pseudotumors are a subset of usually primary and localized idiopathic fibroinflammatory disorders. We report on a 66-year-old man who developed this condition along the facial tissue planes with extension into the orbit and preferential involvement of the periorbital membrane. Fibrocollagenous tissue with scattered lymphoid aggregates without follicle formation dominated the process. There was a light dispersion of B and T lymphocytes and histiocytes in the stroma. Immunoglobulin G4 (IgG4)-positive plasma cells (>35 per high-power field) were identified mostly in the lymphoid clusters, as has been discovered in similar IgG4-related fibrosclerosing conditions of other nonorbital sites. No associated systemic disease emerged during a 20-year clinical course. Previously reported orbital cases of IgG4-positive disease have all involved the lacrimal gland, usually bilaterally, and more closely resembled hypercellular reactive lymphoid hyperplasias with moderate interlobular fibrosis, rather than representing an essentially sclerosing process from the beginning.