The view of Islamic art as a minor art and its various ornaments as without any purpose or meaning is questionable since such a perspective ignores the great influence of the Islamic religion on it. This study investigates in close detail the philosophy of ornament in Islamic art. Clearly, Islamic ornamentation plays a central role in Islamic art and architecture. It is divided into four main elements: Arabic calligraphy, vegetal and geometric ornament, and human and animal figural representation. Due to the significance of Islamic ornamentation, this study will examine its origins, development and impacts on the art and architecture of other cultures as well as the influence of other cultures on the development of Islamic ornamentation. It will also examine the rich historical and cultural background from which the art of Islamic ornament emerged in order to identify the characteristics of Islamic ornament in the context of history, its development, its aesthetic values and its underlying philosophy and forms of expression. In this study the historical survey method is employed to examine the development of Islamic ornamental elements. This study also explores the various Islamic ornamental methods and techniques that artists used to create beautiful Islamic ornaments as well as the meanings of Islamic ornamental symbols in both Islamic art and architecture. This study identifies the most important factors contributing to the beauty of Islamic ornamentation. The nature of the relationship between Islamic artists and spectators and their roles in the context of Islamic art also is examined. The thesis concludes that Islamic ornamentations are based on a divine philosophy that stimulates contemplation of God's Majesty and transcendence through wonder at the cosmos He has created. Another important characteristic of Islamic culture is its acceptance of cultural variations which it absorbed and then used to develop its own unique character and identity. Finally, the study identifies two types of Islamic ornamentation, namely, secular ornamentation and pure Islamic ornamentation, and offers a contrastive definition of both.