With the expansion of urbanization and the development of new cities in Iran, the aesthetic quality of residential environments has become one of the main challenges of urban planning. The aim of this study is to explain the mechanism of the relationship between neighborhood aesthetics, residential satisfaction, and perceived livability and to identify the factors affecting it in the neighborhoods of the new city of Pardis. The present study is an applied study in terms of purpose and a mixed method of sequential description in terms of method. In the quantitative part, the relationships between variables were examined by distributing a questionnaire among 407 residents and using structural equation modeling (SEM). In the qualitative part, semi-structured interviews with 15 experts and field observation were used. Exploratory factor analysis identified five main components of aesthetics: visual appeal, sense of order, public safety and security, absence of pollution, and physical identity. The results showed that neighborhood aesthetics have a positive and significant effect on residential satisfaction. However, its direct effect on perceived livability is not significant, and residential satisfaction plays a full mediating role in this relationship. The mediation of satisfaction was complete for the components of visual appeal, sense of order, and physical identity, and partial for safety and lack of pollution. Qualitative findings indicate that weak infrastructure, urban services, management and maintenance, vitality of public spaces, and sense of social belonging are the most important factors weakening the effect of aesthetics on livability. The contribution of the research is to explain the mechanism of the effect of neighborhood aesthetics on perceived livability, in which residential satisfaction is introduced as a necessary intermediary link and a necessary condition for realizing this effect in the context of new cities (Tehran Campus New City). In general, improving livability in new cities requires integrated attention to aesthetic qualities, residential satisfaction, and physical, social, and managerial dimensions of the urban environment; In a way that improving infrastructure and urban services, enhancing the quality of public spaces, and strengthening the identity and sense of belonging of residents, provides the basis for improving the quality of residence and perceived livability.