Urban river valleys in Tehran, particularly the Farahzad River, have faced environmental, social, and cultural challenges in recent decades. However, their rehabilitation has created significant potential for revitalizing social life and enhancing urban vitality. This study examines the effects of the socio-cultural rehabilitation of these spaces on the social dimensions of urban vitality. The research is applied in purpose and descriptive-analytical in nature, using a mixed quantitative-qualitative approach within a case study framework. Data were collected through library research, urban documents, field observations, and a researcher-made questionnaire. The statistical population consisted of 30 experts, including faculty members and urban managers. The questionnaire included 24 items based on physical, social, and cultural-recreational dimensions. Its validity was confirmed through expert judgment, and its reliability was verified with a Cronbach’s alpha of 0.70. Data were analyzed using indicator ranking and SWOT analysis. The findings indicate that rehabilitation has had a positive effect on urban vitality by increasing social presence, improving environmental perception, strengthening social interactions, and fostering an initial sense of place attachment. The strongest impact was observed in environmental liveliness. However, social insecurity, harmful behaviors, inadequate welfare services, and weak coherence in cultural programs have limited the sustainability of this vitality. Therefore, sustainable urban vitality in these spaces requires the integration of physical interventions with social management, enhanced security, improved welfare services, and participatory cultural planning.