The United Nations Environment Programme Finance Initiative (UNEP FI) published a policy brief assessing how five ASEAN Member States’ sustainable finance taxonomies compare with the regional ASEAN Taxonomy, finding a trend toward greater regional harmonization in key design features. The brief, covering Indonesia, Malaysia, the Philippines, Singapore and Thailand, maps alignment across environmental objectives, approaches to assessing substantial contribution, sector prioritisation, and the use of “Do No Significant Harm”, remedial measures to transition, and social aspects. It finds that all taxonomies include climate change mitigation and adaptation, while some add national priorities such as biodiversity protection, circular economy and marine resource management; Malaysia and the Philippines use principles-based assessments, Singapore and Thailand rely on technical screening criteria, and Indonesia combines both approaches. Despite differences in the maturity of sector-specific criteria, sector coverage overlaps significantly and alignment with the ASEAN Taxonomy is increasing as national taxonomies expand. UNEP FI notes expectations of further evolution through regular updates, greater transparency such as public disclosure of eligibility criteria, and regional collaboration, and points to lessons for ASEAN Member States that have not yet developed taxonomies, including Indonesia’s dual assessment approach and Singapore’s involvement in the Multi-jurisdiction Common Ground Taxonomy to support cross-border interoperability.