Introduction. Grandparents, in particular, are recognized as the "first line of defense" when families are disturbed, disorganized, or in need, often contributing time, care, and financial resources as needed. The ties between grandparents and grandchildren are known for their diversity of content, covering a wide continuum of care and intergenerational support. This study aims to identify, evaluate, and summarize the best available scientific evidence about the influence of grandparents on grandchildren. Method. A systematic search of the relevant literature was conducted in the PubMed, EMBASE, Cochrane Library, CINAHL, PsycINFO, SciELO SCOPUS, WEB OF SCIENCE, and LILACS databases, for articles published up to February 8, 2021, relating to studies evaluating the influence of grandparents on grandchildren. Results. 13 cross-sectional studies were selected. In five studies, financial issues are analyzed and in eight studies nutrition issues are evaluated. The studies were from four different continents – Oceania, Asia, North America, and Europe. Conclusion. Grandparents in the caregiver role influence the grandchildren's upbringing and this influence is linked to the amount of time they spend together. Culture and ethnic factors have a strong impact on this influence. Grandparents contribute to grandchildren concerning finances, regardless of social class or educational level. However, with food, grandparents with a lower educational level than their children, tend to provide a less healthy diet for their grandson. Thus, grandparents are a very valuable audience in awareness campaigns about infant feeding to reduce childhood obesity.