This chapter reviews the predominant normative direction in the relatively new field of behavioural public policy - i.e. that we ought to be aiming to improve internalities so as to increase utility. The chapter critiques this approach, and highlights where reciprocity sits in a suggested alternative political economy of behavioural public policy. It is postulated that conditions be created to nurture reciprocal behaviours, to help people to flourish in both meeting the already predetermined broadly defined objectives of public sector services and in relation to their meeting their privately held goals, where they may find fulfilment in any way they wish. In any way they wish, that is, so long as they are not imposing harms on others. The second arm of the proposed framework is that any harms that are consequent on behaviourally informed actions are potentially fair game for regulatory control. So, in short, it is proposed that the political economy of behavioural public policy be focused upon promoting flourishing and curtailing harms.