Background: Cultural clubs involve a variety of programs and classes that seek to enhance the culture and identity of the citizens. The present study determined the effect of informal education by cultural centers on Shiraz citizens’ development, social excellence, and citizenship culture. Methods: The study was a descriptive and applied research. The population included citizens, who attended cultural center classes (N = 230). Overall, 145 participants were selected based on the Morgan Table (132 females and 11 males) and through simple random sampling. Two questionnaires, including social identity and citizenship culture, were used. The reliability and validity (0.81) of both were confirmed and determined. The data was analyzed descriptively and inferentially (Pearson test and regression model) by the SPSS version 22 software. Results: The results of the social identity questionnaire was average, according to the median of 56, and that of the citizenship culture questionnaire was good, according to the median of 90. The analysis showed that informal education by cultural centers affected social identity (P = 0.002 < 0.01); rule conformity affected social identity (P = 0.001 < 0.01); rule conformity predicted social identity with a proper coefficient; responsibility affected social identity (P = 0.00), this was a good predictor of social identity; and finally, participation affected social identity (P = 0.00). Conclusions: Given the role of informal education provided by cultural centers in citizens’ development and social excellence and culture, using this educational method would be of great help for the society.