Social stratification scholars have expanded from conventional two-generational to three-generational studies to assess family-based inequality properly. However, the heterogeneous effects of grandparents on children are unknown. Therefore, this study examined heterogeneous effects of grandparents based on outcome distribution using residualized quantile regression. The results revealed that grandparents positively affected granddaughters at upper-middle in children’s distribution measured by upper secondary education in Japan in 2012. This indicated that the effects of grandparents’ status on granddaughters occur on the borderline (i.e., whether women enroll in university), as women’s enrollment rate in university at that time was under 50%. This study contributes to understanding inherited inequality based on descendant groups, suggesting that inherited inequality arises heterogeneously.