In Islamic arts, the importance of the harmony between manifest appearance and its deep meaning as well as structure is an undeniable fact. In this context, using fundamental principles that rise from deep structure guarantees the harmony. Horizontality is one of these guiding principles that, when used in Islamic architecture, makes this art unique by way of its deep-seated spiritual origins. This principle is not only found in spaces and ornamental patterns of Islamic architecture, but arguably it has developed roots in the Muslim artist’s life approach and his way of thought. In this paper, using simulative research method, the mechanism of utilization of horizontality in creation of Islamic Architecture is to be perceived. First, a conceptual model is proposed which elaborates the creative process of making artworks from basic, internal principles and the important role of these principles in the design process. Following, the principle of horizontality in Islamic architecture is redefined and re-presented. This paper argues that utilization of horizontality is the consequence of holistic view of the artist from above. Also, adherence to the theosophical belief of Vahdat Vojūd (Unity of all Existences), which is based on Islamic Monotheistic worldview, gives 6 Quarterly First Year, No. 2 spring 2012 the Muslim artist a specific interpretation, which differs greatly from that of the humanist or even Christian artists. The Muslim artist considers his inner being as the seat of God (Allah) and it is from this stance that he views all his surroundings, including architectural space. From this point of view, there is no opposition, no borders and no directions. Instead, everything revolves around equality and infinity. Thus, everything is horizontal.