The rise of populism represents a threat to constitutionalism, democracy, and the rule of law. Populist governments are a threat to the international legal order and to the authority of international legal agreements. This article will, therefore, look at the serious threat to international law that is presented by populism. This fundamental threat to international institutions, multilateralism, and the funding received by NGOs Non-Governmental Organisations (NGOs) is based on the promotion by populist governments that the edicts of international law are merely a matter of coordination and interventionism. Populists and populist governments traditionally promote this ideal through their policies, which are anti-pluralist and are focused on a limited set of agenda-setting goals that are in opposition to the fundamental international goal-setting of protecting human rights, along with the collective agreements between nations for the enhancement of the international community. This article will ascertain the very real threat that is posed by the continued rise of populism and, in particular, a populist government.