This article addresses three basic analytical questions: what is 'decentring regulation', what is 'self regulation' and how does it fit in the decentring analysis, and what meaning is given to 'regulation' to allow it analytically to be 'decentred' - how do we know 'decentred regulation' when we see it? Decentring is a term which is often used to encompass a number of notions, and has both positive and normative dimensions. It is used to express the observation that governments do not, and proposition that they should not, have a monopoly on regulation and that regulation is occurring within and between other social actors: there is 'regulation in many rooms'. Decentring is also part of the globalisation debate on the one hand, and of the debate on the developments of mezzo-levels of government (regionalism, devolution, federalism) on the other. Decentring is also used in a positive sense to describe the consequence of a particular analysis of social systems, in which politics and administration are, like law or economics, are described as being self referentially closed sub-systems of society, incapable of observing other systems except through their own distorted lenses; decentring is thus the removal of government and administration from the conceptual centre of society. Finally, developing from these observations (and mixing metaphors), decentring can be used, positively and normatively, to express 'de-apexing': the removal of the state from the conceptual hierarchy of state-society, and the move to a heterarchical relationship in which the roles of governors and governed are both shifting and ill-defined. The themes of 'decentring' are reflected in a changed understanding of regulation. In that changed understanding, self regulation plays a particular role both in practical policy debates and in more conceptual discussions. The role ascribed to self regulation, however, differs quite fundamentally in those debates. For some self regulation is the solution to the limits of 'centred' regulation; for others it is the challenge that has to be addressed: regulation of self regulation is the new challenge. The prescription is for governments to regulate self regulation in a 'post regulatory' way. But what conception of 'regulation' is thereby entailed? The article deconstructs the notion of 'regulation' and attempts to build an understanding of 'regulation' that can withstand 'decentring'