Objectives This study aimed to evaluate the effectiveness of the Jeollabuk-do Suicide Prevention Training Program for professional gatekeeper instructors, using psychological questionnaires. Methods Eighty-three participants were recruited from mental health centers and relevant organizations in Jeollabuk-do. All the participants were randomly assigned to either an experimental group (n=41), where they took part in the suicide prevention training program developed by Jeollabuk-do for professional gatekeeper instructors, or a control group (n=42), receiving no treatment. Four participants from the control group dropped out, and the final participants for each group were 41 and 38. We analyzed the changes in the two groups, before and after the program, using the Korean Suicide Literacy Scale, Counselors’ Professional Scale for Self-injury Behaviors, Attitudes towards the Suicide Scale, and Help-Giving. Results Participants in the experimental group exhibited a significant improvement in their knowledge of suicide prevention and their attitude toward suicide compared to those in the control group. Conclusion This study suggests that the Jeollabuk-do Suicide Prevention Training Program for professional gatekeeper instructors may serve as an effective means of improving the participant’s knowledge of suicide prevention and changing the attitude towards suicide, and may fulfill its purpose of preventing suicides.