Background: This study focused on poor coping flexibility, which involves the perseveration of a failed coping strategy, as a moderator of the association between depression and suicidal risk; no study has previously examined the association between coping flexibility and suicidal risk. Aims: This study examined whether individuals with lower coping flexibility would have a stronger suicidal risk when experiencing depression above a certain level. Method: Participants, who were 682 college students, answered questionnaires regarding coping flexibility, depressive symptoms, and suicidal risk. Results: Hierarchical multiple regression analyses showed that in individuals with greater depressive symptoms, lower coping flexibility was associated with higher suicidal risk, but this was not the case in individuals without depressive symptoms. Our hypothesis was supported. Limitations: Our findings cannot indicate the causal direction of the association between coping flexibility and depressive symptoms and suicidal risk. Conclusion: Our findings may be useful in understanding the association between depression and suicidal risk through coping flexibility and contribute to reductions in suicidal risk, as coping flexibility can be improved through training.