This research is a comprehensive study of the effects of the development of secondary residences on the economic and social structures of rural areas of Astara County. This research is applied in terms of purpose and descriptive-analytical in terms of method. The required information and data on the economic and social effects of secondary residences were collected through field and library studies. The statistical population of this study is the villages of Astara city. The statistical sample was determined using the Cochran formula and was 358 people. The data were collected through a questionnaire and analyzed using SPSS and Excel software. In the inferential statistics section, after proving the normality of the distribution using the Kolmogorov-Smirnov test, all hypotheses were analyzed using the one-sample t-test. The results showed that the greatest impact of the expansion of secondary residences was related to economic effects (income) with an average of 3.43, and the least impact was related to social effects (education) with an average of 1.99. The research findings show that the formation and expansion of the phenomenon of secondary residences has had significant impacts on economic and social transformations. The findings of this study can provide a basis for local managers and policymakers in planning and managing the development of second homes in rural areas. Accordingly, it is recommended that, while taking advantage of the potential of second homes to increase the income and employment opportunities of local residents, greater attention should be paid to strengthening local community participation and improving infrastructure and social services, particularly educational services. Such measures can help reduce the negative impacts of second-home development and contribute to achieving balanced and sustainable rural development.