Giovanni Boccaccio is one of the key authors for understanding the overlap between medieval and humanistic-Renaissance Italian culture. In this thesis, I focus on Boccaccio's conception of Fortuna, examining three of his texts. Starting with the claims he makes about Dante's conception of Fortuna in his Esposizioni, I emphasize that whilst Dante is much more concerned with the metaphysical dimension, Boccaccio changes the plane of inquiry to investigate the human, the practical, the countersense to the ups and downs of Fortuna. In his proposal, ethics and hermeneutics are closely linked. I argue that this movement contributes to the structuring of both the Decameron and De Casibus Virorum Illustrium. Both texts contaminate the medieval literary genres with which they are affiliated, namely, the collection of exempla and the didactic treatise, making it possible for Boccaccio to propose an interpretive paradigm intended to be valid for informing human moral action.