When the conceptual framework of sustainable development has been proposed in the mid-19th century, social sustainability as a one of its triplet aspects has been always considered as an emerging area. However, in urban plans and programs improvement of social suitability has not got enough attention in design policies and strategies framework.

The issue of how the social sustainability in urban design and public realms can be improved through the urban design knowledge and profession is a required exploration and compilation of scientific responds.

In our research, the elements which make promotion in social sustainability has been investigated and a conceptual framework based on combination of these elements is proposed. The main question evaluated in this paper is “In the field of urban design which factors could be considered as effective elements in order to improve social sustainability".

In order to answer this question, “qualitative content analysis” method was applied to analyze the data. At the beginning of this research, there were 84 factors referring to social sustainability are extracted and categorized. Then, based on its objective, the research concentrated on local elements. In the next step, these codes were reduced from 28 to 18 codes, and they were separated again in three categories of “form”, “concept” and “function” which are in similarity and compliance to the “Canter” famous model. The ultimate model, encompasses 18 urban design elements could be the answer of the proposed question.

Through this method, in the category of “form”, environmental desired quality, designed urban escape, attractive public realm, environmental arrangement, density and compaction are considered as effective elements to develop social sustainability. In the “concept” category these factors are sense of attachment to place, identity of community, character of neighborhood, vernacular/local specifications and perception. Furthermore, in the category of “function”: safety and security, mixed development, pedestrian-orientation, accessibility, environmental infrastructures, facilities, inclusion and diversity were considered as the most important indicators requiring consideration in the field of urban design to develop social sustainability.