The global health community is focusing on immunization in relation to universal health coverage, targeting missed populations and closed communities. However, there are widely acknowledged historical politico-economic factors affecting UHC. In high-income countries, there is continued resistance to immunization within some communities, and in lower income countries, recurring challenges over the elimination of poliomyelitis remain despite massive efforts. The links between religion and vaccination have been obvious for decades. However, there is little analysis of engagement with religious actors in immunization intervention, nor are there many models for engagement. We synthesise available evidence on religion and immunization.