Introduction: The purpose of this study is to understand the role of suicide literacy and suicide stigma in laypeople’s intention to recommend professional help in Korea. Additionally, the study focuses on the role of expressive suppression as a sociocultural factor. Methods: Participants read vignettes depicting either subclinical distress or suicidal ideation and answered questions measuring suicide literacy, stigma, and expressive suppression. Mediated moderation analyses were used to examine the interactions between these factors. Results: The result found the significant effect of emotional suppression. The mediating effect of suicide stigma on the relationship between suicide literacy and recommendation of professional help was significant for those who do not suppress their emotions. This result indicates that when individuals were not hesitant to express negative emotions, high suicide literacy lowered suicide stigma and led to more willingness to recommend professional help. Conclusions: The results showed that emotional suppression acts as a barrier deterring Koreans from professional help for their mental health. The findings underscore the importance of sociocultural factors such as emotional suppression in developing suicide prevention strategies.