This article reviews Dutch contributions to international law and focuses on the last 100 years to mark the centenary of the Netherlands Society of International Law. It poses the question whether this is a missionary burden, resulting from the constitutional duty incumbent upon the Dutch government to ‘promote the development of the international legal order’, or enlightened self-interest on the part of the Netherlands. The article briefly recalls the two Hague Peace Conferences of 1899 and 1907 and Dutch initiatives for a third that had been planned for 1915 at a time when the Dutch pursued a policy of neutrality. It also reviews some Dutch initiatives in the context of the League of Nations and Dutch policy during the San Francisco Conference that established the United Nations in 1945. The German occupation and membership of the United Nations marked the real end of the Dutch policy of neutrality. From the outset, the Netherlands became an active participant in nearly all principal fields of the United Nations' activity. The article highlights a number of Dutch international law initiatives in the fields of human rights, development, peace and security, international humanitarian law, and the peaceful settlement of international disputes. It concludes with final observations on the preoccupation of the Netherlands with international law.