Across the globe, the well-being of newborns is significantly influenced by the knowledge and practices of family members, yet global health policies and interventions primarily focus on strengthening health services to save newborn lives. Predominant approaches to promote newborn survival in non-western cultures across the Global South are based on a western, nuclear family model and ignore the roles of caregivers within wider family systems, whose attitudes and practices are determined by culturally prescribed strategies. In this paper, I review evidence of a neglected facet of newborn care, the role and influence of senior women or grandmothers.Based on a family systems frame, I reviewed research from numerous settings in Africa, Asia and Latin America that provides insight into family roles related to newborn care, specifically of grandmothers. I identified primarily published studies which provide evidence of grandmothers' role as culturally designated and influential newborn advisors to young mothers and direct caregivers. Research from all three continents reveals that grandmothers play similar core roles in newborn care while their culturally specific practices vary. This review supports two main conclusions. First, future newborn research should be conceptualised within a family systems framework that reflects the structure and dynamics of non-western collectivist cultures. Second, newborn interventions should aim not only to strengthen health services but also influential family caregivers, particularly grandmothers and the indigenous social support networks of which they are a part, in order to improve family-level newborn practices and save newborn lives.