The aim of this cross-sectional study was to determine the predictors of health-promoting behaviors among freshman dental students at Istanbul University. Data were collected from a convenience sample of 111 students using questionnaires including a sociodemographic section, the Health-Promoting Lifestyle Profile II, the Health Value Scale, the Generalized Self-Efficacy Scale, the Perceived Stress Scale, and the Multidimensional Scale of Perceived Social Support. Data were analyzed using descriptive statistics, t-test, Pearson's correlation, and stepwise multiple linear regression. The overall health-promoting lifestyle behaviors among these students were at a moderate level, indicating that they engaged in health-promoting behaviors sometimes to often. They scored highest on the spiritual growth but lower on the health responsibility subscales. Females reported having engaged more in health responsibility behaviors and lower in physical activity than did males. Students from high-income families reported more physical activity. Significant correlations were found between overall health-promoting lifestyle behaviors, self-efficacy, health value, stress, and social support. Among all the related factors, self-efficacy was the most strongly predictive factor: it explained 61 percent of the variance in overall health-promoting behaviors. Thus, self-efficacy as a cognitive-perceptual factor should be considered by dental educators when planning educational interventions to promote students' healthy lifestyle.