National human rights institutions (NHRIs) are key domestic mechanisms for promotion and protection of human rights. The institutions' broad mandate, competencies, and special status between state and nonstate actors on the one hand, and special status between the national and international levels on the other hand enable them to engage effectively in the field of business and human rights. Since 2009, NHRIs have been engaging with the international human rights system in order to increase understanding and raise awareness of their role in addressing business and human rights issues. As a result, they have contributed to the development of the UN “Protect, Respect and Remedy” Framework and obtained an evolving role within all pillars of the framework and in its implementation. This paper presents how these domestic institutions, bridging the national and international levels, fit into the UN legal regime for corporate responsibility for human rights and what contribution they make to the implementation of the UN Guiding Principles.