This chapter relates how justice comes to be on the Epicurean view by examining in detail the Epicurean account preserved in Lucretius’ On the Nature of Things V. In doing so, the chapter shows that the Epicureans are defenders of a kind of social contract theory and so side with defenders of nomos in the nomos-phusis debate. Nevertheless, their conception of nomos is importantly constrained by phusis. Furthermore, the chapter also argues against those readers who have characterized the Epicurean account of the social contract as Hobbesian. If the Epicurean account is to be assimilated to a modern view, the ideas of Jean-Jacques Rousseau are a much better fit.