Abstract: The subject of this research is the phenomenon of "virtual reality" in architectural environment. The article provides an overview of the emergence of idea of "virtual reality" in science and architecture. The trends of metaphoric definition of the term in various field of humanitarian knowledge are examined. Special attention is given to the theoretical questions of the phenomenon, history of its origin, and consideration of ontological approaches. The author determines the role and correlation of the visual illusions with virtual reality, when the significance of illusory effects comes to the forefront of manifestation of the phenomenon in architecture. Methodology of this study lies in the gradual examination of the questions related to the analysis of historical materials, emergence of the idea of virtual reality, issues of visual perception of the architectural environment and illusory architectural spaces. The main conclusion consists in peculiar understanding of the phenomenon of “virtual reality” in architecture. The author gives definition from the perspective of the theory of architecture; identifies the types of phenomena of illusory nature; as well as substantiates the significance of illusory effects in the context of formation of virtual reality of the architectural environment that can be valuable in theory and practice.