One of the consequences of the increased use of adjudicative procedures to resolve environmental disputes is that it has raised the expectations of international civil society that states can now be more effectively compelled to observe their environmental commitments. Much as public interest environmental litigation has been pursued in some domestic jurisdictions, it is contended that international courts may be used by environmental NGOs and other private actors to ‘defend the environment’. Against the background of such expectations, the three sections of this chapter consider whether it is indeed possible and appropriate to speak of public interest environmental litigation on the international plane. The first section surveys the changes in international environmental law through which private actors have come to assume important roles in the formation and operation of environmental regimes. In the second section the chapter examines the extent to which civil society has been granted access to adjudicatory bodies resolving environmental disputes. It is contended in the third section that the character of public participation in most judicial and quasi-judicial bodies deciding environmental disputes bears only limited resemblance to domestic public interest environmental litigation. None the less, through the reception by some courts of amicus curiae briefs it is increasingly possible for international adjudication to be responsive to interests of community concern that lie at the heart of much international environmental disputation.