This chapter analyses the motivations of economic actors in classical Athens from the point of view of modern behavioural economics. The (now) old orthodoxy of M.I. Finley, drawing on Bücher and Weber, stressed that the so‐ called homo economicus did not exist until recent times: in antiquity, an anti‐productive mentality was essentially hard‐wired into the minds of elite Greeks and Romans, preventing economic development. This approach has been widely rejected in recent years, and in particular the methods of New Institutional Economics (NIE) have provided a way around the moribund formalist‐primitivist debate. Yet whilst NIE has provided a set of important analytical tools, it would be an exaggeration to claim that these tools can solve every problem relating to economic activity in antiquity; here, the insights of behavioural economics can assist us in understanding economic activity in past societies.