Objectives: Evaluate college students’ preventive dental behaviors based on the Health Belief Model (HBM), identify key constructs of HBM to promote preventive dental behaviors, and determine the impact of the COVID-19 pandemic on college students’ preventive dental behaviors. Methods: The data for this cross-sectional study were collected from 550 college students (ages 18 to 25; 69.8% female) through an online survey. Participants were recruited through a random sampling process. Descriptive statistics were used in the analysis of quantitative data. A multivariate analysis of variance was applied to examine the relationship between HBM and preventive dental behaviors. In addition, chi-square was used to determine the prevalence of preventive dental behaviors associated with dental knowledge. Results: Perceived barriers and self-efficacy were significant predictors of preventive dental behaviors (p < 0.001). Also, a significantly higher proportion of students with sufficient dental knowledge met the recommendations for tooth brushing and dental checkups compared to those with deficient or moderate dental knowledge (p < 0.05). Although most of the participants reported no influence of COVID-19 on their preventive dental behaviors, a considerable number of the students still reported the influences of COVID-19 (tooth brushing: 20.9%; tooth flossing: 10.6%; dental checkups: 18.8%). Conclusions: The Health Belief Model could be an effective framework to promote preventive dental behaviors for college students, particularly, using perceived barriers and self-efficacy.