Despite the high prevalence of mental health issues in adulthood, scholars have yet to fully explain the social conditions that contribute to poor mental health outcomes. One important gap in the existing literature is the impact of multigenerational caregiving on the mental well-being of adults whose parents are part of the sandwich generation. Using seven waves of linked mother–child data from the National Longitudinal Surveys (2008–2020) and growth curve models, I examined (1) the relationship between mothers’ caregiving for both older and younger generations and depressive symptoms in their adult children, and (2) whether this association varies by adult children’s age. Findings suggest that maternal sandwich caregiving does not significantly predict adult children’s depressive symptoms overall. However, the association differs by age: maternal sandwich caregiving is particularly detrimental to the mental health of older adult children compared with their younger counterparts. These results highlight the need for continued research on the collateral consequences of sandwich caregiving, especially as this caregiving arrangement becomes a reality for millions of American families.