This report is the result of an evidence and landscape review commissioned by the Bill and Melinda Gates Foundation to better understand how gender inequalities influence a wide variety of maternal and newborn health (MNH) behaviors and outcomes across low and middle-income countries. Based on a systematic analysis of peer-reviewed academic literature, program reports, evaluations and case studies, as well as interviews with key stakeholders in the MNH health sector, it provides evidence on how gender inequality contributes to the vulnerability of pregnant and newly parenting women and girls and their newborns. It also highlights lessons learned from interventions that have addressed gender norms, including programs targeting maternal empowerment and men’s role in MNH to improve health outcomes. The review demonstrates that increased attention to gender in MNH programming by the BMGF would be a very welcome and much needed contribution to the field.