A growing body of research has shown the positive contribution of grandparents to adolescents’ well-being. However, studies often overlook the cultural context in which this relationship is embedded. The current study examined whether emotional closeness to the grandparent identified by the adolescents as their closest grandparent varied among Arab and Jewish adolescents and whether cultural affiliation serves as a moderator in the association between emotional closeness to grandparents and adolescent adjustment difficulties and prosocial behaviors. The study was based on a sample of 2,751 Jewish and Arab secondary school students (aged 12-18) from Israel who completed a structured questionnaire. Among the whole sample, greater emotional closeness to the closest grandparent was associated with reduced emotional symptoms, reduced hyperactivity, and increased prosocial behaviors. While there were lower levels of emotional closeness to the closest grandparents among Arab adolescents, emotional closeness to grandparents was found to be more strongly associated with reduced emotional symptoms and increased prosocial behavior among Arab adolescents than among Jewish adolescents. These findings emphasize the importance of considering culture when examining intergenerational relationships in the family and their contribution to grandchildren’s well-being.