In this paper, we exploit pension reform-induced changes in retirement eligibility requirements to assess the role of grandparental childcare availability in the labor force participation of women with children under 15. Our analysis shows that, among the women studied, those whose own mothers are retirement eligible have a 11% higher probability of being in the labor force than those whose mothers are ineligible. The pension eligibility of maternal grandfathers and paternal grandparents, however, has no significant effect on the women’s labor force participation. We also demonstrate that the eligibility of maternal grandmothers mainly captures the effect of their availability for childcare. Hence, pension reforms, by potentially robbing households of an important source of flexible, low-cost childcare, could have unintended negative consequences for the employment rates of women with young children.