The purpose of this study was to examine the prevalence and predictors of suicidal behavior among Mongolian high school students. Females were more likely to have suicidal behavior than males. No close friends, feelings of loneliness, insomnia, self perception of underweight or overweight, carrying a weapon were significant predictors of students’ suicidal behavior. Missing school without permission, being bullied and going hungry were also important risk factors of suicidal ideation. Families and Schools are important environments to prevent high students’ suicide. Improving students’ psychological well being, quality of relationship with people, and support resources are critical to prevent suicidal behavior.