The diagnosis of numerous lesions are essentially based on the microscopic study of cells and tissues. Hematoxylen and eosin staining is an established and age old, gold standard procedure for diagnosing all histopathological tissues. Despite this, H & E sections are undoubtedly insufficient at a diagnostic level when one engages in an etiologic, histogenetic or pathogenetic search, leading to invariable exploration for additional techniques. In the era when advanced immunologic and molecular techniques are used for diagnosis of disease and for its classification, pathologist relying entirely on the examination of tissue sections stained by histochemical methods is gradually being replaced. One such procedure is the immunohistochemistry which has revolutionized the field of surgical pathology during the past 50 years. A variety of markers are developed which are tissue/ organ specific like epithelial markers, lymphoid markers, vascular markers and are used successfully as diagnostic and prognostic markers of diseases. The main aim of this review is to enumerate and discuss the role of various markers used in the diagnosis of various oral lesions. The applied method of the search stratergies were books, printed articles, google, and pubmed database. The numbers of studies screened were fifty seven and included in the review were thirty nine, since the review was concerned only with oral potentially malignant disorders and oral cancer. This comprehensive review on role of immunohistochemistry in diagnosis of various oral lesions- A review, is attempted to highlight the importance of immunohistochemistry in diagnosis and prognosis of various oral lesions.