This review of significant international environmental law cases covers the period from May 2017 to June 2018. This year has seen a number of novel issues being addressed by international courts and tribunals. Firstly, the International Court of Justice (ICJ) has dealt with the question of compensation for transboundary harm for the first time (see Section 2). Secondly, the Inter-American Court of Human Rights (IACHR) has grappled with the issue of transboundary protection of human rights, a question that has often been raised in the literature, but never authoritatively addressed by an international court or tribunal (see Section 3). Finally, investment treaty tribunals have been faced with interpreting recently negotiated treaty provisions which seek to strike a balance between investment protection and the prevention of environmental harm (see Section 5). The survey also reveals new international court and tribunals emerging onto the scene, with the first decision of the African Court on Human and Peoples’ Rights in relation to environmental issues. All-in-all, the survey demonstrates the continuing dynamism and expansion of international environmental jurisprudence and the substantive contribution that international courts and tribunals are making to the development of international environmental law.