Objectives: The purpose of this study was to examine factors influencing the mental health of high school students in relation to sociodemographic variables, family function, self-esteem, social support, and self-identity. Methods: The survey was carried out on a convenience sample of 332 high school students. Data analysis procedure included stepwise regression using mental health as the dependent variable, and sociodemographics, family function, self-esteem, social support, and self-identity, as independent variables. Results: Stepwise multiple regression revealed that the factors such as self-esteem(${eta}=0.422$, p<0.001), self-identity(${eta}=0.166$, p<0.001), and sex(${eta}=-0.165$, p<0.001) turned out to be significant affecting factors. Twenty seven percent of varience in mental health was explained by these factors(22% of varience by self-esteem). Conclusion: Self-esteem was turned out to be the most important effective factor of mental health in high school students. These results suggest that it is important for high school students to promote their self-esteem to keep their good mental health.