Many political leaders of the Global South oppose linkages between trade liberalization and environmental protection. We field-tested a combination of surveys and conjoint experiments in Costa Rica, Nicaragua, and Vietnam to examine whether citizens in developing countries share this position. The results show that citizens do not view economic integration and environmental protection as a trade-off. To the contrary, individuals with greener preferences are more supportive of trade liberalization. Furthermore, and in contrast to prevailing government rhetoric, the majority of citizens support environmental clauses in trade agreements. These findings suggest that there might be room for more ambitious efforts to include environmental standards in international trade agreements.