As environmental problems today are understood as being problems of collective action, they also depend on the broad engagement of individual citizens for their successful solution. Policymakers are thereby faced with the challenge of designing policy and constructing policy tools, which contribute to an increase in individual environmental responsibility and voluntarily behavioural change. Here, this challenge is approached from the point of departure of policy legitimacy, concluding that the problem of legitimacy facing public policy is threefold: affecting the performance (in terms of effectiveness and efficiency) of political programs and policy tools; the boundaries of the policymaking process itself (through the legitimacy/effectiveness dilemma) as well as the democratic standing and future overall performance of political government. As such, the thesis aims both at exploring the level of legitimacy for contemporary Swedish environmental public policy as well as at analysing the prospects and prerequisites for designing future environmental policy that holds a high(er) level of legitimacy. In order to fulfil these aims, a further objective is to discuss the meaning and function of policy (as opposed to political-) legitimacy as well as to suggest methods and approaches to its study.By reviewing and synthesising key concepts and theories from legitimacy theory, public opinion research, and policy analysis, as well as from social and environmental psychology, the first part of the thesis constructs a framework for studying policy legitimacy, focusing content rather than process or actors, and systems of belief rather than opinion. The level of policy legitimacy is seen as the extent to which values and beliefs underpinning public policy content corresponds to those established among the public. This suggests that the evaluation of policy legitimacy is a three-step process, requiring an exploration of policy belief-systems; a mapping of public belief-systems and a subsequent comparison of the two.In the second part of the thesis, the analytical framework is put to the test in an empirical exploration of the legitimacy for Swedish environmental public policy during the period 1994-2006. By examining and comparing data from a qualitative text analysis of national policy documents with the results of two mass-surveys conducted in the years of 2004 and 2006, important insights are reached in terms of how both policymakers and the public understand and frame the environmental problem in terms of causes, seriousness and possible solutions; how they assign costs and responsibilities in amending the problem; as well as their preference for overall goals in the environmental policy domain. The thesis concludes that although public policy and public values align on several instances, belief-system divergences potentially affecting policy performance might nevertheless be identified. These findings deepen our understanding of the character of those legitimacy issues facing Swedish environmental public policy, providing relevant insights into how the level of legitimacy, and thereby policy performance, might be furthered. Lastly, it is possible to conclude that through the elaboration of an analytical framework, contributions are made to the scientific study of policy legitimacy, also beyond the environmental policy domain. / Godkänd; 2009; 20090813 (simon_m); DISPUTATION Ämnesområde: Statsvetenskap/Political Science Opponent: Professor Neil Carter, University of York, United Kingdom Ordförande: Professor Torbjörn Bergman, Luleå tekniska universitet Tid: Fredag den 18 september 2009, kl 10.00 Plats: A 109, Luleå tekniska universitet