This paper addresses the overall performance and inequalities in the immunization of children in Vietnam. Descriptive and logistic analysis of cross-national demographic and health data was used to examine inequality in immunization, identify the most vulnerable groups in immunization coverage, and identify the gap in coverage between hard-to-access people and the remainder of the population. The gap in the coverage was found to occur primarily in vulnerable groups such as the poor minority or poor rural children. No evidence was found of a difference in immunization coverage because of sex or birth order. However, the age of children showed a significant influence on the rate of immunization. Mother's education and regular watching of television had a significant influence on child immunization. In order to improve child immunization coverage in Vietnam, efforts should be concentrated on poor children from minority groups and those living in rural areas, especially remote ones. Community development, investment for immunization and re-organization of immunization services at the grassroots level are also key factors to remove the barriers to immunization for vulnerable populations in Vietnam.