Traditional economics served as the model case of most early performativity theory. In recent years, however, behavioural economics and particularly nudging has become increasingly popular; both as a policy instrument to design markets and as a behaviour change tool used by for-profit organizations. This chapter unpacks the implications of this shift in economic discourse for performativity theory, examining to what extent the performative process of behavioural economics overlaps with standard performativity and how it differs from that of traditional economics across policy and business domains. We focus on four aspects of the shift: (1) the nature of the economic subjects – consumers, workers, market actors – being performed, (2) the changes in the underlying normative standpoints and the politics of performativity, (3) the technologies of knowing adopted, and (4) the performative actions and socio-technical assemblages facilitated by traditional versus behavioural economics. The chapter concludes by offering a theoretical extension of performativity theory and a critical account of the potential impacts of behavioural economics and by laying the groundwork for future research.