The historical origin of the concept of intentionality is commonly traced to scholastic philosophers’ reception of Avicenna’s concept of maʿnā. Recently, many scholars have challenged this narrative and, as a result, initiated a debate among Avicennian scholars about whether maʿnā bears any connection to intentionality. My dissertation reconstructs Avicenna’s theory of maʿnā and intentionality to offer a new perspective on this debate. I begin by developing a focal- meaning reading of maʿnā. Although maʿnā means different things in different contexts, the different senses point to a focal meaning: maʿnā is the non-sensible cognitive factor. Thus, maʿnā is related to intentionality insofar as apprehending maʿnā goes hand in hand with intentionality. Any apprehension that receives or processes maʿnā is intentional. I then further investigate Avicenna’s view on the nature of intentionality through the metaphysics of intentional apprehension. I examine in what sense Avicenna thinks that the mental existence of maʿnā makes possible our knowledge of non-existent objects. His metaphysical picture is that quiddity has a two-way existence: concrete and mental existence. Concrete existence refers to the expression of quiddity in the world, whereas mental existence refers to the unveiling of quiddity in the mind. When a quiddity is unveiled in the mind but not expressed in the world, the mind then grasps knowledge of the quiddity that does not exist in the external world. This picture suggests that, for Avicenna, the nature of intentionality involves thinking about things such that the quiddity of things exists-in- the-mind. I call this position ‘the existential account of intentionality’. Aboutness, for Avicenna, is primarily a feature of a fundamental way of existence. Third, I explore whether Avicenna’s existential account of intentionality is committed to a naturalistic or phenomenal consciousness approach. I argue that neither approach characterises Avicenna’s account. Instead, Avicenna offers an alternative to both relational intentionality and phenomenal intentionality. Although Avicenna accepts that intentional states presuppose pre-reflective self-awareness, this self- awareness is not a phenomenally conscious state because it is the state of being essentially intellectual. Finally, I turn to Avicenna’s theory of intellectual cognition and explore it through the lens of my existential account to offer a nuanced answer to the exegetical concern about whether humans obtain intelligibles by abstraction or emanation. As a result, I consider a number of questions about how the existential account is consistent with Avicenna’s cognitive psychology. In the final chapter, I address two problems. First, I clarify how my account extends to apprehension of the estimative faculty. Second, I discuss how the existential account relates to Avicenna’s theory of conceptual acquisition.