Do governmental investors such as sovereign wealth funds (‘SWFs’) have a legal duty to protect the natural environment for future generations? After providing a background on SWFs, the paper examines the relevant international law paradigms, with a particular focus on the concept of intergenerational equity – the notion that the state must preserve access to environmental resources for future generations. The article asserts that SWFs, as state actors, have a legal responsibility under international treaties and customary international law, as well as the evolving rules on complicity in international jurisprudence and general principles of international human rights law (which the author posits form the basis for intergenerational equity and environmental rights), to adopt environmental intergenerational equity as an overarching investment policy and implement the principle through shareholder activism and ESG screening.