This review of significant international environmental law cases covers the period from June 2019 to May 2020. In line with the general trend in recent years, the case law during this period has largely been driven by specialist courts and tribunals operating within a particular field of international law, such as international human rights law or international investment law. However, the past year has seen some contributions to the jurisprudence from domestic courts applying international rules and principles, as well as from ad hoc arbitral tribunals constituted for the purpose of settling inter-state disputes.