The present study was carried out to detect the importance of INF gamma gene polymorphism in the susceptibility to oral lichen planus lesions. The present study was performed on a total of 50 individuals, 30 oral lichen planus patients (10 from each type: atrophic, papular, bullous erosive lichen planus) not taking any drug that may cause lichenoid reaction,20 control individuals not suffering from any mucosal lesion as well as matching the oral lichen planus patients regarding age . Blood samples were taken from each patient and control and stored at -20 till DNA extraction. DNA was extracted from the whole blood by using DNA extraction kit. The results revealed no statistically significant difference in T_allele distribution among different types of OLP neither when all patients were considered as a whole not when they were considered as separate groups. But there was highly significant increase in the frequency of TT genotype among OLP patients compared to controls. Conversely, there was an increase in AT genotype in controls. So, it seemed that INF-γ gene polymorphism contributes to the predisposition to OLP. Where patients carrying TT homozygous genotype have about 5 times more risk of developing OLP, while those with AT heterozygous genotype have low risk of developing OLP. Also that genetic variation of INF-γ gene seems to affects the gene expression and may contribute to the disease chronicity, particularly that when cases with reticular pattern were analyzed, the risk was found to increase to 8.5