The death of a spouse is a major life event, commonly experienced in later adulthood. While existing research suggests that widowhood may reduce the provision of grandchild care, most studies have relied on cross-sectional comparisons between widowed and non-widowed individuals. In this study, we use longitudinal data from the Survey of Health, Aging, and Retirement in Europe (SHARE; n = 27,467) to examine how changes in partnership status are associated with grandparental caregiving over time. Using panel fixed effects regression models, we find that widowhood significantly decreases grandchild care provision among grandfathers but not among grandmothers. For grandfathers, grandchild care declines by approximately 13 days per year shortly after widowhood, 19 days 2 years after, and 16 days 4 years after, relative to pre-widowhood levels. In contrast, the effects for grandmothers are small and statistically non-significant. These findings suggest that in contemporary Europe, grandfathers substantially reduce their caregiving involvement following the loss of a spouse, whereas grandmothers’ provision of grandchild care remains largely resilient to widowhood.