Closing the gap between current and attainable crop yields is essential for improving global food production. Expanding irrigation and using more fertilizers can help achieve this, but these strategies also require more energy and can increase greenhouse gas emissions. In this study, we assessed where closing yield gaps would be both economically worthwhile and environmentally manageable. We found that 31% of global harvested cropland—mainly in China, Nigeria, the Democratic Republic of Congo, Myanmar, and Indonesia—could close yield gaps cost-effectively, adding $76 billion in value and feeding 746 million more people each year. However, fully closing global yield gaps would double agricultural energy use and raise emissions by 2%, placing notable pressure on countries like India, Pakistan, and many in Sub-Saharan Africa. Reducing the scale of yield gap closure to 75% or 50% would lower both energy use and emissions, but trade-offs remain. Our findings show large differences between regions in economic returns, energy needs, and environmental impacts. This highlights the importance of designing region-specific strategies to improve food production while minimizing negative consequences for climate and energy systems.