Objective: Oral mucosa exposed to many external factors. It has been suggested that oral pathologies may be related to cell-mediated immunity. Dendritic cells are antigen presenting cells that initiate adaptive cellular response. Langerhans cells(LCs), an important member of this group. Oral lichen planus(OLP) is a common chronic mucocutaneous inflammatory disease of unknown etiology. The most common malignancy in the oral cavity is oral squamous cell carcinoma(OSCC). In this study, we aimed to understand the role of LCs in OLP and OSCC which has an important role in mucosal defense.