<p>Numerous studies have explored the link between co-rumination and depressive symptoms, but a consensus remains elusive. This study proposes a dual-pathway model to explain this relationship through a “positive path” (adaptive response) and a “negative path” (distress response). It also conducts a meta-analysis to evaluate the exact association between co-rumination and depressive symptoms in children, adolescents, and young adults. A total of 66 studies (27,794 participants) were included in the meta-analysis. In this study, the main effect test revealed a significant positive correlation between co-rumination and depressive symptoms (<i>n</i> = 70; <i>r</i> = 0.128; 95% CI = 0.106 to 0.150). Moreover, age was found to be a significant moderator. Specifically, the association between co-rumination and depressive symptoms was weaker in adolescents compared to undergraduates and adults. In addition, measure of co-rumination was identified as an important moderator, showing marginal significance. The association was stronger when using the original Co-Rumination Questionnaire compared to other versions and code methods. Finally, the relationship between co-rumination and depressive symptoms was not moderated by gender, measure of depressive symptoms, publication year, study quality, or simple size. The current study reveals the positive association between co-rumination and depressive symptoms while highlighting both the positive and negative trade-offs of co-rumination.</p>