This thesis analyses the concept of 'chance' as it is understood by two Muslim philosophers, Ibn Sīnā (Lat. Avicenna, CE 980-1037) and Ibn Rushd (Lat. Averroes, CE 1126-1198). On the philosophical plane, I seek to ascertain whether they are determinists, i.e., whether they hold that everything that happens is necessarily conditioned by its causes so that it could not have been otherwise. This analysis discusses chance from a physical and a metaphysical perspective. Physics is here understood in the Aristotelian sense as the study of nature and change, and metaphysics as the study of being qua being (ontology) and of the divine (theology). Hence a particular stress on natural causation and on divine providence and causation. On the historical-philosophical plane I endeavour to determine the historical/philosophical sources of their views, namely the Graeco-Arabic philosophical tradition - Aristotelian and Neoplatonic on the one Band, and the tradition of Islamic theology (kalām) on the other. Particular emphasis is laid upon the original way in which Ibn Sīnā and Ibn Rushd combine these two traditions.