Research on co-rumination has investigated its relationship with internalizing symptoms, but few studies have addressed underlying maladaptive cognitive-affective processes that may play an important role in the maintenance of this relation. This study examines if Young's schema domains mediate the relation between co-rumination and depression in a community sample of non-clinical young adults. Participants completed the Co-Rumination Questionnaire, Young Schema Questionnaire-L3, and Teate Depression Inventory. Correlations and path analysis were calculated for the full sample and separately by gender. The schema domains of Overvigilance/Inhibition and Other-Directedness fully mediated the relation between co-rumination and depression. When analyses were performed separately for males and females, mediation persisted only for females. Findings suggest that among young women, co-rumination with a friend may be associated with depressive symptoms because of its activation of specific maladaptive cognitive schemas. Better understanding of the content and processes underpinning co-rumination may have important implications for the prevention and treatment of depression.