Geoengineering has generally been a research province of the Global North. Developing countries, especially climate-vulnerable regions such as Southeast Asia, have made few contributions to a critical understanding of geoengineering. To deliver more climate action, we need to amplify Global South voices in this debate. This essay summarizes the deliberations of a workshop that sought to build an inter- and multi-disciplinary knowledge community on the critical study of geoengineering in Southeast Asia. Held in Indonesia, this workshop involved discussions among 17 social science researchers, climate modelers, environmental policy analysts, and civil society actors from the region. On the basis of in-depth discussions, research themes were developed to help guide future geoengineering research in Southeast Asia. These themes included: biochar techniques for carbon capture and storage; expansive modeling of regional impacts of stratospheric aerosol injection, especially for transboundary water bodies; national and regional governance implications of carbon dioxide removal and solar radiation management; and critical social study of these technologies. The workshop participants called for support for regional research on geoengineering through new funding opportunities and increased international collaboration.