Purpose: Youth suicide is a serious problem in schools, but fundamental courses linking the subjects of suicide prevention and mental health promotion are lacking. This study evaluated a 3-credit-hour course within the undergraduate general education program over an 18-week semester with the aims of mental health promotion and suicide gatekeeper training. Methods: The course design was based on a pragmatic approach which covered topics from mental health literacy to suicide prevention. We focused on examining the students' knowledge and attitudes about suicide myths and mental health promotion by using a 25-item Suicide Myth Questionnaire (SMQ) before and after the course. Outcome evaluation targeted changes in correct responses at pre-course, post-course and 4-month follow-up based on results on the SMQ. Results: A total of 47 students completed the whole course. The majority of students showed positive changes on most items about their attitudes, and learned about suicide warning signs in the course. The correct response rate (CRR) for items, dimensions, and total SMQ scores improved significantly after the course. The study revealed the effectiveness of the course and the limitations of items about myths with lower CRRs. Conclusions: The preliminary findings supported the positive effects of mental health literacy education for undergraduate students. Concepts with less favorable outcomes will influence the future design of a course about mental health literacy and suicide prevention in universities.