ASEAN’s growing population and economy make its climate ambition vital to global mitigation. While all ASEAN Member States (AMS) updated their Nationally Determined Contributions (NDCs) in 2020–2021, current emissions trajectories fall short of 1.5–2°C goals. Varying mitigation targets complicate comparisons, but using an assessment framework, AMS were grouped by ambition levels. Cambodia, Laos, and Myanmar showed progress in expanding targets; Brunei, Singapore, and Vietnam improved coverage but face perception gaps; Malaysia and the Philippines improved economy-wide targets but need clearer sector plans; Indonesia and Thailand offered minimal updates and should provide more detail in future NDCs for support and alignment.