This research examines whether and why people manoeuvre their unethical behaviour so as to maximize material gains at a minimal psychological cost. Employing an anonymous die-under-cup paradigm, we asked people to report the outcome of a private die roll and gain money as a function of their reports. Supporting self-concept maintenance theory, results showed that people avoid both major lies (i.e. over-reporting the highest possible outcome) and minor lies (yielding little material gain), but did over-report intermediate outcomes when this implied a substantial increase compared to a walk-away value. Results suggest that lying is psychologically costly. We propose that organizations allowing freedom of choice while narrowing the available ways to unethically boost personal profit should see a decrease in unethical behaviour among their employees. © 2010 British Academy of Management.