There is a dearth of information on childhood vaccination coverage in Bangladesh. Thus, this study aimed to investigate the associated factors and changes in childhood vaccination coverage over time in Bangladesh. Bangladesh's Demographic and Health Surveys from 2011, 2014, and 2017-18 provided data on vaccination coverage for children aged 12 to 35 months. For three survey periods, multilevel binary logistic regression models were employed. The overall prevalence (weighted) of full vaccination among children aged 12-35 months was 86.17% in 2011 and 85.13% in 2014, and 89.23% in 2017-18. Children from families with high wealth index, mothers with higher education, and over the age of 24 and who sought at least four ANC visits, as well as children from urban areas were more likely to receive full vaccination. Rangpur division had the highest change rate of immunization coverage from 2011 to 2014 (2.26%), whereas Sylhet division had the highest change rate from 2014 to 2017-18 (34.34%). To improve immunization coverage for Bangladeshi children, policymakers must integrate vaccine programs, paying special attention to mothers without at least a high school education and families with low wealth index. Increased antenatal care visits may also aid in increasing the immunization coverage of their children.