Development informal residential spaces in cities and especially metropolitan areas, provides a concept of quality of urban life which needs to be upgraded and reconsidered. In this regard, Present study focuses on informal communities and identify the quality components related to the built environment in terms of objective qualities and subjective qualities in relation to residents' satisfaction with the settlement in the form of physical–spatial characteristics with their irreplaceable roles in determining the residents' lifestyle. In this research, to achieve the goal, both qualitative research method and survey strategy are applied. Data collection is done through literature review, and also field impression of space users along with survey analytical method of Fuzzy Delphi and Entropy Shannon Technique. In the part of documentary study, 33 quality components are achieved and evaluated from the perspective of "improving the quality of informal settlements" via Delphi Method. Through initial screening, 9 components and in the following according to experts' consensus 3 more components are removed from the list. As a result, the study attains 21 qualitative components which are categorized into 2 main dimensions of objective and subjective qualities and 7 thematic categories in following. Finally, findings from analyzing the indicators using Shannon Technique show that the dimension of "Residential Satisfaction" and the category of " safety and security" are having the most impact on enhancing the quality of informal settlements. As well, among single indicators, "crime prevention", "accessibility and permeability" and "facilities and infrastructure" are the highest influencers in the list.
