Intergenerational solidarity is crucial to address the care needs of aging societies. Many research efforts have dealt with the question why and to what extent children are looking after parents in need. Although care for parents essentially takes place in parent-child dyads, some of these studies acknowledge that the amount of care a child gives is generally the outcome of collective decisions in multiple-child families. However, to our knowledge, no research in Europe enhances our understanding on how sibling characteristics influence an individual child’s caregiving. We use data for 18 European countries from the Survey of Health, Aging and Retirement in Europe (SHARE) to illuminate the role of sibling characteristics, such as gender composition and care opportunities, in explaining differences of children’s caregiving for parents. The analysis focuses both on absolute and relative measures of sibling characteristics. The outcomes show that daughters’ care provision increases when they have brothers instead of sisters, confirming the gendered nature of informal caregiving for parents. Moreover, the results point in the direction of persistent gender role expectations as an explanation for gender differences in caring within the family. Our findings also demonstrate that emotional closeness and geographic distances between siblings and their parents influence the care decision of children. Children being closer to their parents than their siblings in terms of emotional relationships and geographic proximity tend to have higher odds of caring for their parents. This suggests that individual characteristics facilitating caregiving are also considered at the family level to make care decisions. Hence, the role of siblings in children’s caregiving decisions cannot be neglected.