Background: Engaging adolescents in mental health education programs can markedly improve their knowledge, decrease stigma, and enhance professional help-seeking. Two-step study was carried out. The first step was applied to 416 secondary school students in two Egyptian Governorates, using an adapted version of a questionnaire used to survey beliefs and attitudes towards mental illness and professional help-seeking. The second step, a health education program, was implemented upon 224 students; they were classified into intervention and control groups. The program was done to improve their knowledge and attitude. Results About 8% of participants had positive findings suggestive of mental illness; the commonest disorder was anxiety disorder (3.9%). Although most of the participants had a positive attitude towards a mentally ill person, 70.7% of them considered mentally ill persons dangerous, and 60.3% will be ashamed if they/their relatives have a mental illness. The main station of seeking help if having a mental trouble was friends (38.9%). The intervention succeeded to change the belief that mental illness is like any other illness from 46.4 to 96.4%. It decreased the belief that mental illness is an evil spirit from 38.4 to 6.3%. Attitude was improved after intervention for all items except in the point of marrying a person with mental illness. Help-seeking from family members or healthcare workers was significantly improved after the intervention. Conclusions Anxiety was the commonest mental disorder among the studied group. Negative attitude and wrong beliefs can be changed with health education. Low professional help-seeking may arise the need for more effective professional interventions.