Oral Potentially Malignant Disorders (OPMDs) are defined as lesions with a greater likelihood of progressing to cancer. Population-based studies that evaluate the prevalence of OPMDs are scarce in Brazil. The aim of the present study was to determine the prevalence of OPMDs and associated risk factors in a semi-urban Brazilian population. This is a cross-sectional study, whose universe included individuals aged 40 years or older residing in a medium-sized city of northeastern Brazil. Data collection was divided into two steps: interview and oral examination. The outcome variable was the presence of OPMDs. The predictor variables were sociodemographic characteristics and risk habits. The bivariate analysis was performed through chi-square test. The crude prevalence ratios (PR) and its respective 95% confidence intervals (CI) were calculated. Poisson regression analysis with robust variance was used to calculate adjusted PRs and 95% CI. Three hundred fourteen individuals were included in the study. When asked about risk habits, 58.9% reported being current smokers or ex-smokers and 62.2% reported being current drinkers or ex-drinkers. The prevalence of OPMDs was 7.6% and was significantly higher among individuals with black skin color (p < 0.001), alcohol users (p = 0.017), and individuals with both tobacco and alcohol habits (p = 0.012). Therefore, the population in the present study had a high frequency of risk habits associated with PMDs of the oral cavity.