Any attempt to offer an account of natural law in Stoicism is confronted with the notorious problem of evidence. Not a single work of the ‘early’ Stoics (Zeno of Citium, Cleanthes and Chrysippus, all working in the third century BCE) has fully survived from antiquity. Reconstructions of their views depend on reports by authors who wrote much later and are in many cases anything but unbiased. The information that these authors provide usually leaves a rather wide scope for different interpretations. And the decision between these interpretations is often a matter of the general assumptions which guide our approach to the Stoics: whether we tend to think, for instance, that the early Stoics stood on common ground with their predecessors and contemporaries or whether we assume that they tried to distinguish themselves from other philosophers. As we shall see, this alternative is particularly relevant in the case of the natural law.