This chapter explores the complex and multifaceted relationship between international trade and environmental protection. The global trade regime's normative principles, legal rules, and real-world consequences often contradict environmental governance. For example, there is tension between trade and environmental governance with respect to the commercialisation of endangered species, export of hazardous wastes, emissions involved in transporting goods, and patentability of living organisms. However, there are also synergies, which enable trade liberalisation and environmental protection to reinforce one another. For example, trade forces were key drivers in the reduction of ozone-depleting substances and the affordability of pollution abatement technologies. The chapter explores these conflicts and synergies by first discussing the literature that examines the positive and negative impacts that trade has on the environment. It goes on to look at the trade dimensions of various environmental regimes, and then environmental dimensions of the trade regime, within both the World Trade Organization and preferential trade agreements.