Background: Oral Lichen Planus (OLP) is a chronic inflammatory disease affecting the oral mucosa in 0.5-2% of the world's population. It is more common in women compared to men and the mean age at the onset of the lesion is the fourth decade. Objectives: The purpose of this study was to evaluate the presence of Helicobacter pylori (H. pylori) in Oral Lichen Planus and Oral Lichenoid Reaction. Materials and Methods: A total of 41 biopsies diagnosed as Oral Lichen Planus and Oral Lichenoid Reaction and 15 samples as the control group were selected from the archives of Pathology Department of Loghman Hakim Hospital, Tehran, Iran from 2002 to 2009. All the paraffin blocks were cut for hematoxylin and eosin (H and E) staining to confirm the diagnoses and the samples were then prepared for immunohistochemistry (IHC) staining. Statistical analysis was performed using SPSS statistical software (version 21.0), the chi-squared test and Fisher's exact test, and independent-samples t test. Statistical significance between the groups was set at P < 0.05. Results: The H. pylori positivity was found in 29.7% and 14.8% of OLP, and OLR samples, respectively. Statistically significant difference was not observed compared to normal tissues (P = 0.661). The chi-squared test show no significant difference between the frequency of H. pylori positivity and the lesion type, gender, and site. Although H. pylori positivity was found in 59.2%, and 50 % of OLP, and OLR samples, respectively, statistically significant difference was not observed compared to normal tissues (P = 0.838). In addition, the chi-squared test show no significant difference between the site of the lesion and H. pylori positivity. H. pylori positivity was mostly found on the buccal mucosa (64.3%), however, H. pylori negativity was mostly found on the tongue (60 %) (P = 0.309). Additionally, the chi-squared test show no significant difference between the frequency of H. pylori positivity, and the gender (P = 0.517). Independent-samples t test showed no statistically significant difference between age and two patient groups statistically (P = 0.450).Conclusions: This present study reveals no significant difference between the presence of H. pylori in OLPs and OLRs. Yet, further studies with larger sample size needs to be done to prove this association.