This paper provides an overview of population dynamics and scenarios of population change in the environmentally vulnerable coastal Ganges Brahmaputra Delta region. The main data sources used for the study include the historical and most recent Census data, data from Sample Vital Registration System (SVRS) and Demographic and Health Surveys (DHS). The research adopts the standard cohort component approach for population projections and provides population estimates for the period 2011-2051. The results include scenarios of future population change in the coastal Ganges Brahmaputra Delta (GBD) and district-level population projections by age and sex. The results show that population growth is likely to continue in some, but not all, districts in the study area. The findings also suggest that migration is most likely to be the deciding component of population change in the region. The paper concludes by discussing selected policy implications in the context of expected changes in population structure in the Ganges Brahmaputra Delta, including population aging and rapid urbanisation in some districts.