AbstractIn recent years, children across the globe, such as Greta Thunberg and Kelsey Juliana, are seen at the front line of efforts to hold governments accountable for environmental damage. In the Philippines, the case of Oposa v. Factoran gave legal standing to minors and unborn generations invoking their constitutional right to a balanced and healthful ecology. The Philippine Supreme Court based its decision on intergenerational equity—a principle stating that every generation has an obligation to protect the environment for the next.Representation of future generations in courts is not a new concept, nor is it unique to the Philippines. By examining national laws, treaties and conventions and court decisions by both domestic and international courts, this article aims to show how intergenerational equity has been widely recognised by almost all countries globally as evidence of state practice and opinio juris.This article argues that the principle of intergenerational equity is ripe for consideration as customary international law and discusses how domestic and international courts and tribunals have been instrumental in establishing such and recommends that children and unborn generations be given legal standing as a necessary consequence.