Economic inequality, as one of the most important metropolitan challenges, has wide-ranging consequences on sustainable development, social justice, and urban cohesion. The present study was conducted with the aim of investigating and identifying the factors affecting economic inequality among Tehran citizens. The research method is descriptive-analytical and its approach is mixed; quantitative data was collected through a structured questionnaire and qualitative data through semi-structured interviews. The statistical population includes households in 22 districts of Tehran, from which 400 valid questionnaires were collected through stratified random sampling. Data analysis was performed using a multivariate regression model and thematic coding. The findings show that variables such as differences in access to job and educational opportunities, income gap, discrimination in the labor market, concentration of capital in the housing sector, and inequality in the provision of urban services play a decisive role in intensifying the class gap. Also, intra-urban migration and inefficient housing policies have led to the concentration of poverty in peripheral areas and deepened the economic gap. Qualitative results indicate that a sense of injustice and a decrease in social capital are direct consequences of these inequalities. Based on the final analysis, a combination of structural (such as economic policies and urban planning), institutional (such as weak tax system), and individual (such as education level and job skills) factors are effective in shaping this situation. This study suggests that urban policymakers should provide the basis for reducing economic inequality in Tehran by reforming the income distribution system, strengthening education and skills training, and balanced development of urban services. The results of the research can be used as a basis for decision-making in urban planning and designing justice-oriented strategies in the management of the Tehran metropolis.