This research analyzes the influence of selected social psychological factors (health locus of control and health value), social support factors (influence of parents and peers, organizational involvement, and reliance on others during stressful times), and health-specific factors (recent health crisis and self-assessment of health status) on participation in health protective behaviors by males and females. While much research has focused on identifying determinative factors (often with inconsistent findings), little research has been directed to understanding if and how predictive factors vary by gender. Data for the research were obtained from personal interviews with 167 undergraduate college students collected during the fall semester of their freshman year and again during their sophomore year. Female students averaged statistically significant more health protective behaviors than did male students, and increased involvement in HPBs from their freshman to sophomore years (while male students' participation declined). Among the factors studied, peer practices (collected in time 2) is a statistically significant predictor for both males and females. Value placed on health predicts for females but not males, while grade point average predicts for males but not females. Overall, females and high GPA males are most likely to engage in HPBs.