This study provides a comprehensive examination of the environmental consequences of foreign direct investment (FDI) within Vietnam’s agri‑food sector, focusing on the tension between agricultural expansion and carbon emission control. In the context of rising global climate concerns, the analysis examines how FDI inflows affect CO2 emissions, while considering agricultural structural transformation, economic development, and trade openness. The results indicate that FDI significantly increases CO2 emissions, primarily through scale expansion and structural shifts toward emission-intensive agricultural activities. The findings underscore agricultural industrial restructuring as a crucial transmission channel. The study contributes both theoretically and practically by offering policy recommendations aimed at steering FDI toward cleaner agricultural development pathways and supporting Vietnam’s transition toward a low‑carbon and climate‑resilient agri‑food system.