Background: Suicide is one of the highest causes of mortality in all around the world. Anyone could be the victim of suicide, including teenagers. Teenagers are the age group which is vulnerable to the experience of psychosocial changes, and is potential to committing suicide. Based on the data, some of the suicide victims are teenagers. Nowadays, there have been facts and myths about suicide spreading around the societies. The knowledge and the ability to differentiate between facts and myths about suicide is significant in order that one could have better perception. Studies have shown that psycho education is able to decrease wrong perceptions and on the other hand improve one’s knowledge. Therefore, psycho education is needed to improve teenagers’ knowledge about suicide as well as to help them avoid it. Purpose: To find out the effect of psycho education on the teenagers’ knowledge level about facts and myths of suicide in SMK YAPPI wonosari. Research Method: This research was using quasy experimental non-equivalent control group design. This research design was effective for evaluating the medical education or training program. 29 samples for each experiment and control group were taken through purposive sampling from Grade 10 students. The respondents were given pre-test questionnaire, followed by 4 counseling sessions. The post-test was given to the experiment group at the end of the psycho education session. The data analysis was conducted through paired T-test to see the difference between the pre and post-test score of each group, whereas unpaired T-test was used to compare the post-test score between control and experiment group. Result: There is significant difference of knowledge level in experiment group after the psycho education (p=0,000). Unpaired T-test data analysis shows p=0,007, indicating that there is significant difference of knowledge level between control and experiment group after the psycho education. Conclusion: There is psychoeducation effect on the teenagers’ knowledge level of facts and myths about suicide in SMK YAPPI Wonosari.