The writings of al-Jahiz are regularly adduced as an example of Hellenism's early impact on medieval Arabic intellectual culture. His relationship to Aristotle in particular is a growing preoccupation among scholars, who have nevertheless done little more than enumerate al-Jahiz's many borrowings from and disagreements with "the author of the Organon" [sahib al-Mantiq]. My paper proposes a more sophisticated model for the relationship between these two thinkers, one predicated not on mere "debt" but a nuanced "influence" more usually invoked by poetic criticism than in history of philosophy. For it is not the case that citations of Aristotle sit inertly within al-Jahiz's texts. In fact al-Jahiz is in relentless dialogue with his predecessor, often treating him more as a rival than a source. It will be observed that al-Jahiz's overt borrowings from Aristotle are matched by his covert reworkings of received Aristotelian paradigms. These latter escape notice without close attention to the corpus of Aristotelian texts available in al-Jahiz's day – above all the paraphrase of the Organon by Muhammad b. 'Abd Allah b. al-Muqaffa' (son of the better-known author of Kalila wa-Dimna). My focus is on the third section of the Organon, which is the Peri Hermeneias (Aristotle’s treatise "On interpretation"), and two important revisions of its doctrines by al-Jahiz. The first of these is Aristotle's claim that assertoric statements can only be true or false; the second is the four-part semiotic paradigm (consisting of writing, "things in speech," "things in the soul," and external pragmata) with which Peri Hermeneias begins. In his own treatment of these questions al-Jahiz does something very telling, which is to make expansions on the Aristotelian paradigm without naming Aristotle explicitly. So it is that to the categories of truth and falsehood al-Jahiz adds a third category, which is the factually incorrect statement made in genuine ignorance without the intention to lie. And in place of Aristotle's semiotic model (prefaced by Ibn al-Muqaffa' with the dictum "these matters have four aspects") al-Jahiz will develop a five-part semiotic model in his books al-Hayawan and al-Bayan wa-'l-tabyin. In neither case is Aristotle mentioned by name, an omission which is no less significant than the explicit references to Aristotle long noted by readers of al-Jahiz. In so contending, I hope to contribute to a more informed and nuanced apprehension of the medieval Arabic reception of Greek philosophy.