Immunization is one of the major public health interventions to prevent childhood morbidity and death. The Expanded Programme on Immunization has gathered momentum worldwide since 1974. The range of vaccines in the programme is being expanded in the years to come. All across the globe, a high level of vaccination coverage has been reached and now needs to be sustained. In part, the coverage has been made possible by the broad acceptance of vaccinations, although there are variations resulting in different configurations of fully, partially and non-immunized children. Using the results of studies carried out by the Social Science and Immunization Project in Bangladesh, Ethiopia, India, Malawi, the Netherlands and the Philippines, this article describes and discusses patterns of vaccination acceptance and non-acceptance. It shows how context affects acceptance of vaccinations, and analyses the underlying reasons behind refusal and resistance. The article also develops conceptual tools for the analysis of acceptance and non-acceptance and discusses explanatory theoretical perspectives.