This article discusses ecocide in relation to the infamous usage of herbicides during the Vietnam War. Fauzy notes that there are no formal international legal instruments that criminalize the act of ecocide. However, he questions whether ecocide, by its nature, is an international crime. To answer this question, the article identifies different arguments for what makes a crime an international crime from the International Law Commission, the jurisprudence of the ad hoc tribunals, and scholarly debates. Ultimately, the article finds that ecocide is not an international crime according to the parameter of “universally criminal.” because there is no international treaty that criminalizes ecocide, not enough states that deem ecocide as a crime, and no UN General Assembly Resolution that obliged the state to criminalize ecocide. However, the author notes that the environmental destruction in the Vietnam War fulfills the elements of ecocide pursuant to Article 26 of the 1991 Draft Code of Crimes Against Peace and Security of Mankind, due to the willful nature of the widespread, long-term, and severe damage to the natural environment caused.