Measuring the well-being of citizens has become established practice in many advanced democracies. In the move to go beyond GDP, indicators of subjective well-being (SWB) have come to the fore, and are increasingly seen as providing a ‘yardstick’ to guide public policy. A strong version of this position is that SWB can (and should) provide the sole basis on which to design and evaluate public policy. This article argues that the increasing dominance of the subjective definition of well-being is problematic, and amounts to a hegemony of happiness. The article examines the fundamental assumptions behind different accounts of well-being, and develops a critique of the ‘strong position’ that sees SWB as the ultimate guide for public policy. First, the connections between the modern debate and classical schools of thought are discussed, and the strong Benthamite SWB approach is contrasted with the alternative Aristotelian capabilities approach. Next, the article examines current practice, using the UK’s Measuring National Well-being Programme as a case study. Finally, the article concludes that SWB has questionable legitimacy as a summary indicator of objective quality of life, and does not, on its own, provide a reliable metric for public policy. The capabilities approach, which takes a pluralist perspective on well-being and prioritises freedom and opportunity, offers a richer and more useful foundation for policy.