Today’s society is increasingly aware of the fragility of the environment. A considerable amount of international and national laws have been passed to tackle the dangers that threaten our environment. Latin America is among the most biodiverse regions in the world and Latin American countries are increasingly adopting measures to protect their environment. These measures are sometimes challenged by foreign investors invoking international investment agreements (IIAs). Latin American states have also raised defences or counterclaims based on environmental arguments. IIAs play a prominent role in the resolution of investment disputes. Although one of the main goals of IIAs is to protect investments, these treaties have also started to recognize the need to protect certain public interests, such as the environment. However, IIAs’ lex specialis status should not hinder arbitrators from applying other relevant international and national provisions to guarantee that the resolution of investment disputes takes environmental concerns properly into account.