This study aimed at investigating the effect of social capital on sustainable urban development. The research method and data collection tool was a questionnaire. Face validity and construct validity were used for the validity of the measuring instrument and Cronbach's alpha coefficient was used for reliability. The face validity of the measuring tool was agreed by professors and the construct validity and Cronbach's alpha coefficient were also considered favorable. The statistical population consisted of all citizens over 15 years old in Tehran. The sampling method was multi-stage cluster with the Cochran's formula at a level of 5% error, 2000 people were selected for sampling. The sampling method for selecting citizens was also random. Data analysis method was performed using descriptive indicators as well as correlation coefficient and multivariate regression. The software used was SPSS version 26. The results showed that in the indicators of social capital, Social trust is weak and sustainable development with two indicators of productivity and justice also had a lower average than the theoretical average. Findings related to the testing hypotheses also showed that social capital has a significant and positive effect on sustainable urban development. Also the social capital has a significant effect on productivity. And social trust, and social participation, and shared networks and norms, and social cohesion have a positive effect on productivity. Social capital has a significant and positive effect on justice. And social trust, and social participation, and shared networks and norms, and social cohesion have a positive effect on justice. Manuscript profile