PURPOSE: To report the clinical and immunopathologic features and the response to therapy in a series of six patients with cicatrizing conjunctivitis due to lichen planus. DESIGN: Retrospective case series. METHODS: All six patients were seen in an ocular pemphigoid clinic. Clinical, immunopathologic, and serologic features were evaluated and therapeutic response in each patient was monitored. RESULTS: All six patients had evidence of conjunctival scarring. Five patients had lichen planus of the oral mucosa and gingiva; one patient had involvement of the skin. Histologic findings consisted of thickened epithelium and an interface lymphocytic infiltrate along the lamina propria. In three patients, electron microscopy of the conjunctiva revealed thickening, fragmentation, and duplication of the basement membrane zone. Direct immunofluorescence examination of the conjunctiva and oral mucosa demonstrated linear and shaggy fibrinogen deposition along the basement membrane zone, confirming the diagnosis of lichen planus. All six patients were placed on immunosuppressive therapy with control of the disease. However, only one patient was able to discontinue the anti-inflammatory medication and have the lichen planus remain in remission. CONCLUSIONS: Lichen planus should be included in the differential diagnosis of cicatrizing conjunctivitis. Performing appropriate investigations to distinguish conjunctival lichen planus from other autoimmune diseases such as mucous membrane pemphigoid is critical to managing the patient with cicatrizing conjunctivitis appropriately. Oral cyclosporine effectively controlled the conjunctival lichen planus in four of the six cases.