As Southeast Asia reels from the impacts of the coronavirus disease (COVID-19), domestic resource mobilization (DRM) has never been more challenging or more critical. Prior to the pandemic, many countries in the region were not achieving a tax yield of 15% of gross domestic product—the level considered to be the minimum for sustainable development. The pandemic has further reduced tax revenues and public expenditures are facing increasing pressure. This publication identifies technical, policy, and administrative tax capacity issues faced by ten countries in Southeast Asia. It also explores potential policy and administrative measures to strengthen DRM.