Background: Oral squamous cell carcinoma is the most common oral cancer. Oral potentially malignant disorders (OPMDs) can be detected before they turn into oral cancer, thus its prevalence and risk factors should be investigated. Objectives: This research aims to study the prevalence, clinical appearances, histopathological features, and demographic data in patients with OPMDs in Faculty of dentistry, Chiang Mai University during 2017-2020, along with the relationship between dysplasia level and risk factors. Methods: This was retrospective and analytical study. The following data were collected and analyzed according to patient’s diagnosis: demographic data and behaviors, clinical appearances, and histopathological features. Results: The mean age was 60.6±13.0 years, dominate by female (70.9%). The prevalence for each disease was as follow: leukoplakia (28.6%), erythroplakia (8.2%), lichen planus (39.7%), oral submucous fibrosis (2.2%), actinic cheilitis (3.1%), discoid lupus erythematosus (13.3%), lichenoid reaction (1.8%), and candidal leukoplakia (3.1%). Most disorders are found at buccal mucosa as white plaque or mixed red and white lesion along with burning sensation. In histopathological aspect, mild dysplasia was frequently found in all disorders except lichenoid reaction which no dysplasia was found. Fifty-nine percent of patients with smoking history were found with dysplasia while only 21% of non-smoking patients were found with dysplasia. Conclusions: OPMDs are frequently found in elderly patients above 6th decade and mostly found in female patient. Lichen planus was the most common found among OPMDs. In this retrospective study the relationship between smoking habit and dysplasia was found. No malignancy transformation was found during the study period