This chapter begins with an examination of the historical development of Regulatory Governance (RG) in the European Union (EU). It provides the principal conceptual and theoretical contributions made on RG in the EU. EU regulatory governance is carried out through a complex interplay and an evolving balance of power between domestic and supranational factors. Politically, progress in EU RG has been made possible through the political entrepreneurship of EU institutions which seek to identify new areas where regulation can be extended. Irrespective of the fact that EU member states should legally share equal rights and obligations, the EU is far from being a model of unitary RG. The EU features a variety of different, evolving and overlapping regulatory approaches within and across different sectors in which the power of EU institutions varies considerably. The Treaty on the Functioning of the European Union formally clarifies the division of competences between the EU and EU members.