Vaccine preventable diseases have been responsible for a significant portion of childhood mortality in low-income countries, and have been re-emerging in medium- and highincome countries. The effectiveness of routine childhood immunization programs relies on multiple factors. Social determinants have the potential to affect immunization programs around the world, with globalization and ease of communication facilitating their effect. Exploring the types of social determinants affecting immunization efforts in various countries is of great importance to the ability of nations to address them, prevent the spread of disease and lower mortality rates. The social determinants affecting vaccination programs can vary among countries of different income levels, with some social determinants overlapping among these country groups. In this article we explore the various social determinants affecting routine immunization programs in low-, middleand high-income countries and possible interventions to address them.