Purpose: In recent decades, it has been a burgeoning trend in South Korea that older women are more actively engaged in grandparenting (i.e., caring for grandchildren) as they are living longer and healthier lives. The present study examines how grandparenting is associated with the mental health of grandmothers. Design/methodology/approach: Drawing from the Korean Longitudinal Study of Aging (2008–2012, N = 2,814), we used growth curve models to estimate the trajectories of grandmothers’ depressive symptoms by grandparenting type. Findings: The results show that caregiving grandmothers in multigenerational households experience a decline in depressive symptoms with age, despite having a higher mean level of depressive symptoms than non-caregiving grandmothers at age 47; whereas the non-caregiving grandmothers experience an increase in depressive symptoms with age. Grandmothers who provide non-coresident grandparenting (i.e., babysitting) are not significantly different from non-caregiving grandmothers in the rate of increase in depressive symptoms. Originality/value: Grandparenting in multigenerational households may have a beneficial effect on older women’s mental health over time in South Korea. This finding is robust after we control for socioeconomic status, health behaviors, and social support.