Lichen planus (LP) is an autoimmune, mucocutaneous, T-cell mediated chronic inflammatory disease that involves the oral mucosa. The prevalence of LP is 0.04–2% in general population with a female predilection. Patients with skin lesions also manifest oral lesions predominantly and about 25% present with only oral lesions. The aim of the systematic review is to analyze the serum cortisol levels in LP patients to elucidate the role of cortisol in pathogenesis of the lesion. A comprehensive search was done using electronic data bases such as PUBMED, EMBASE, SCIENCE DIRECT, COCHRANE, GOOGLE, manual search, and back references of the articles were extracted. A total of seven relevant articles were reviewed and analyzed. Electronic database and manual search identified 55 articles. Out of which, 33 were excluded after reading titles and removing duplication and 23 studies were evaluated in detail after reading the abstract and full text. A final of seven studies were included based on the inclusion criteria to meet the research question. All the studies analyzed the serum cortisol levels in LP patients and also in healthy subjects. Within the limitations of this review, it can be inferred that Cortisol is an established stress hormone and Serum cortisol estimation could be an important indicator in identifying susceptible oral lichen planus patients.