This article explores the interactions between international environmental law and international investment law. It discusses existing tools and procedural devices available before international courts and tribunals to promote compliance with emerging principles, standards, and commitments relating to sustainability. This article first considers the way in which international courts and tribunals have had recourse to environmental protection through treaty interpretation. It then appraises the various ways that environmental protection is referred to in bilateral investment treaties. Finally, the article explores the procedural devices that could be used to take into account/address environmental considerations within the investment framework.