Societal efforts towards greening the economy are typically accompanied by controversy over whether voluntary initiatives by firms or government regulation are more effective to that end. Recent research shows that public opinion plays an important role in this regard because citizens’ preferences are crucial when democratic policy-makers decide. We investigate whether and how citizens’ general attitudes regarding the relationship between the private sector and government can help explain their policy preferences. We argue that whether citizens perceive the firms-state relationship as synergistic or antagonistic has an effect on their support for private sector self-regulation or government regulation respectively. We assess this argument based on information from a representative survey (N=1677) in Switzerland that covers four green economy issues: environmental impacts of consumption of peat, plastic packaging, climate- (un)friendly pension fund investments, and consumption of clothing. We find that citizens who regard the firms-state relationship in environmental policy-making as synergistic favor private sector self-regulation (with government rules potentially serving as a floor standard). In contrast, citizens who regard the firms-state relationship as antagonistic prefer either self-regulation or government intervention. We also observe that views on whether firms engage in self-regulation to gain a competitive economic advantage shape the perception of a synergistic firms-state relationship. Our findings are relevant to current green economy debates as policy-makers in Europe and elsewhere are trying to move beyond the ‘either firms or the state’ paradigm in regulatory environmental politics.