 This entry aims to offer an account of some of the most representative features of Avicenna’s logic without any pretense to exhaustiveness. A standard classification of the works and contents of the Aristotelian Organon in the Arabic tradition (which includes Porphyry’s Isagoge, alongside Aristotle’s Rhetoric and Poetics) divides the study of logic broadly into two main areas focusing either on (i) formal aspects (e.g., the analysis of the truth conditions of propositions, inference, and the structure of arguments) or (ii) on material aspects (e.g., the classification of arguments with respect to their terms and premises, which underwrites a standard division of logic into five areas: demonstration, dialectic, sophistic, rhetoric, and poetics). The entry focuses primarily on (i) and limits the treatment of (ii) to the case of demonstration and fallacies.