Objective: The present study examined the moderating effect of coping flexibility on the association between the coping waiting patiently for interpersonal stressors and depression. Coping flexibility refers to devising and implementing suitable coping strategies according to the situation, coping was defined in this study as holding oneself back and not acting prematurely to address a stressful relationship. Participants: A total of 481 Japanese college students. Methods: Participants completed questionnaires to measure coping, coping flexibility, perceived stress, and depression using a longitudinal design. Results: Multiple regression analysis showed that an interaction between coping and coping flexibility was associated with depression. This result indicated that higher levels of coping was associated with lower depression 16 weeks later when coping flexibility was higher, but the association was not observed when coping flexibility was lower. Conclusions: Our findings contribute to elucidating the condition or process whereby the strategy of waiting patiently as a coping mechanism for interpersonal stressor reduces depression.