This study has been commissioned by the European Parliament as an input to the discussion on the role of the National Human Rights Institutions (NHRIs) in the implementation of the United Nations Guiding Principles on Business and Human Rights, in particular in Eastern Partnership countries. The study examines the scope of the national institutions’ mandates under the Paris Principles to address human rights and business concerns and provides an overview of the best practices from around the world. The analysis of individual NHRIs’ mandates is focused on NHRIs from non-EU Eastern Partnership countries and complemented with an overview of the role the EU has already played and could play in the future, in providing support to the NHRIs.