This study maintains that the extent of influence exerted by Aristotle on the Stoics has often been exaggerated by modern scholars. A collection of all references to him by authors other than Peripatetics, whether contemporary or belonging to the following century, shows that his importance as a philosopher was not then recognised and reveals a lack of evidence that his school-works were known. Professor Sandbach argues that it is a mistake to proceed on the assumption that the Stoics must have known his work, or even an outline of it, and been stimulated, whether to agreement or to modification. If the supposed evidence for Aristotelian influence is examined without this presumption, much is found to be flimsy and some can be confidently rejected. A residue remains of varying degrees of probability, which it is hard to estimate owing to our insufficient information, particularly about Zeno, about the Academy of his time, about Aristotle's exoteric works, and about memory of him in oral traditions.