This is the final version of the article. Available from the publisher via the DOI in this record.While political scientists concur about the increasing importance of regulation, the extant literature features a notable diversity of contemporary definitions of regulation. The various understandings of regulation put different emphasis on the role of the state and regulation as an instrument or a process, respectively. This article scrutinizes and clarifies the notions of regulation and self-regulation in the Political Science literature. Along three analytic questions – what is regulated, who regulates, and how is it being regulated? –, the essay illustrates developments from regulation as government intervention to regulation as governance...