Nasir Khusraw (394/1003-470/1077) wrote his works during a time when the Dar al-Islam not only allowed, but promoted intense philosophical discussion and debate. Various schools of theology, philosophy and mysticism competed with each other to formulate the most reasonable descriptions of both the form and the content of religion. This paper begins with a review of some of the key thinkers before Nasir Khusraw, briefly summarizing their explanations about iman va ‘aql. The paper then continues to examine Nasir Khusraw’s poetry and his philosophical texts in order to ascertain his own ideas about the relationship between iman and ‘aql.