The relationship between spirituality and urban design is complex. Since the twentieth century, spirituality has often been neglected in western European architecture and urban design education, theory, and practice. My lived experience of the city of Phnom Penh and its dynamic spatial spirituality further highlighted this condition and prompted this research. This thesis explores the relationship between spirituality and urban design with specific reference to the city of Phnom Penh in Cambodia. Based on a combined ethnographic and phenomenological approach, the spatial impacts of spirituality in the urban layout of the city of Phnom Penh were researched through five years of participant observation, twenty semi-structured interviews, photographs, drawings, conversations and relevant literature review. Analysis of the data revealed the prevalent hybrid spirituality of Khmer culture, that includes Animism, Hinduism, and Buddhism, was, and still is, spatially manifest in the urban layout of the city of Phnom Penh in three leading ways. Firstly, through the topographical elements of tree, mountain, and water in their natural, artificial and abstracted presence. Secondly, through both domestic and urban wide scale, where it is evidenced in common housing typologies and significant urban focal points. Thirdly, through a variety of rituals, that include the major national festivals and their associated rituals as well as traditional construction rituals for both settlements and housing. These many and varied spatial impacts of spirituality have dramatically influenced the evolution of the urban layout over time as well as transforming each other. When the layered results were mapped onto a series of plans, elevations and sections, the presence and character of a powerful and dynamic relationship between spirituality and urban design in the city of Phnom Penh in the twenty-first century was clearly demonstrated. Now that a plausible relationship has been rigorously identified and spirituality has been validated as a core design parameter, research can go further into its multivalent character and spatial spiritual impact that could, by extension, inform neighbouring urban layouts within East Asia and beyond
