Sustainable development is an urgent need and an inevitable trend for countries worldwide. Current studies have overlooked the debate on whether government intervention limits or promotes sustainability. This study examines the impact of fiscal expenditure, particularly on education and research and development (R&D), on the sustainable development of eight ASEAN countries from 2004 to 2022. Using Bayesian regression, results show that spending on education and R&D positively impacts sustainable development, with probabilities of 100% and 63.55%, respectively. These findings indicate that fiscal expenditure significantly enhances sustainable development in the ASEAN region, aligning with the context in Vietnam. However, while sustainable development in Vietnam benefits from annual economic growth (GDP) and population growth (POP), these factors have negative impacts on the ASEAN countries. Based on these findings, the authors propose policy implications for the entire ASEAN region and, specifically, for Vietnam.