Sub-Saharan Africa faces immense challenges in spurring economic development and alleviating poverty, while these countries also should protect the environment amid population growth and industrial development. This study analyses the interrelationships between demographic change, economic growth, and pollution in four East African countries – Ethiopia, Kenya, Sudan, and Uganda – from 1990-2019. Using panel data and econometric analysis, the paper examines whether declining fertility rates and parallel diminishing of the youth dependency burdens are associated with accelerated growth and rising emissions. The results affirm that falling fertility has opened a window of opportunity through the ‘first demographic dividend’, which can catalyse growth by increased shares of working-age individuals. However, this growth has been accompanied by rising carbon dioxide emissions, underscoring potential trade-offs between environmental and economic objectives. The findings highlight the importance of complementary health, education, governance, and sustainable production investments for countries to leverage their demographic dividends for inclusive and green growth. Successfully doing so will be vital to achieve multiple Sustainable Development Goals simultaneously.