Countries in the Global South—which are contributing an increasing share of global greenhouse gas emissions—are actively developing carbon market mechanisms, including emissions trading systems and (voluntary) offset mechanisms. This article analyzes past and emerging experiments with carbon market mechanisms in Thailand and Vietnam, in the context of their domestic political economies and the shifting dynamics of the global climate governance regime. Drawing from thirty-three in-depth interviews and document analysis, I show the changing roles of government, the private sector, civil society, and donor and multilateral actors in these countries. Moreover, the article identifies key factors that may play roles in the further—and more synergistic—development of carbon market mechanisms: the generation of domestic demand for carbon credits; building and keeping human capacity and adequate data; creating space for civil society; ensuring coordination within the government and between sectors, notably the energy sector; and establishing further linkages with regional (Asian) and global carbon market mechanisms, such as those in China, Japan, and South Korea. These findings suggest that market-based mechanisms with high social and environmental integrity are one of the options that countries in the Global South have to achieve low-carbon development in the post-Paris climate change regime.