The proposal of the Stop Ecocide Foundation’s Independent Panel of Experts to amend the Rome Statute with a crime of ecocide seeks to bring accountability to those who wreak environmental destruction. Yet the definition leaves questions as to which individuals could be held liable. In this chapter, we examine how the modes of liability in Rome Statute Articles 25 and 28 would assign individual responsibility for ecocide. Like genocide, war crimes, crimes against humanity and the crime of aggression, environmental destruction is frequently brought about by the compounding actions of many individuals. The development of international criminal law has taken place in response to this collective nature, with modes of liability that are specifically tailored to address mass action. Using a hypothetical scenario involving the establishment and operation of a coal mine, the chapter assesses how the Rome Statute’s liability framework might hold individuals responsible for perpetrating, aiding and abetting, failing to prevent and punish, and attempting the crime of ecocide. The chapter offers an opportunity to reflect on the potential scope of the crime of ecocide in its practical application and its adherence to fundamental principles of criminal law. Ultimately, the chapter identifies concerns that the currently proposed definition of ecocide may be too broad and vague, thereby undermining the principle of legality.