Structural changes in the population in recent decades and the increasing number of elderly people in Iranian cities have made the need to redesign public spaces with a human-centered approach a major concern. In the meantime, urban squares, as the beating heart of collective life, play a decisive role in promoting the happiness and social sustainability of this group. The present study aimed to evaluate the social sustainability components of urban squares from the perspective of the happiness of the elderly and with a case study of the Naqsh-e Jahan Square in Isfahan. This research was conducted with a sequential mixed exploratory method and using field observations, interviews with 12 key actors, and a questionnaire among 400 elderly people aged 60 and older. The reliability of the instrument was confirmed by calculating the Cronbach's alpha coefficient equal to 0.83. The data were analyzed with SPSS software. The findings show that among the 25 items in the six main factors, the components of “architectural identity and authenticity” with an average of 4.81, “memorability of space” with an average of 4.62, and “sense of belonging to the place” with an average of 4.45 have obtained the highest score. In contrast, “appropriate rest furniture” with an average of 2.67, “universal accessibility” with an average of 2.84, and “access to restrooms” with an average of 3.02 are the most important shortcomings. The results of Pearson correlation show that all five social sustainability factors have a positive and significant relationship with the happiness of the elderly. The “sensory-psychological” factor has the strongest relationship with a coefficient of 0.92, and “accessibility and transportation” has the weakest relationship with a coefficient of 0.69. Despite its shortcomings, Naqsh-e Jahan Square provides a worthy platform for the happiness of the elderly through its enormous semantic and historical capital.